Summary of Pesticide Use Report Data - 2017

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CALIFORNIA DEPARTMENT OF PESTICIDE REGULATION California Environmental Protection Agency P.O. Box 4015 Sacramento, California 95812-4015 Gavin Newsom, Governor Jared Blumenfeld, Secretary California Environmental Protection Agency Val Dolcini, Acting Director Department of Pesticide Regulation

June 2019

Any portion of this report may be reproduced for any but profit-making purposes.
For information on obtaining electronic data files, see page ii. This report is available on DPR's Web site www.cdpr.ca.gov/docs/pur/purmain.htm. If you have questions concerning this report, contact PUR.Inquiry@cdpr.ca.gov.

Contents

How To Access the Summary of Pesticide Use Report Data

Year in Summary

1.  Introduction

• Continuous Evaluation of Pesticides
• CalAgPermits
• Data Collection
• Improving Data Quality
• Improving Access to the Data

2.  Comments and Clarifications of Data

• Terminology
• Agricultural and Nonagricultural Pesticide Use
• Site Codes
• Unregistered Use
• Adjuvants
• Cumulative Acres Treated
• Number of Applications
• Over-counting Pesticide Use

3.  Data Summary

• Pesticide Use In California

4.  Trends in Pesticide Use For Select Pesticide Categories

5.  Trends in Pesticide Use for select Commodities

• Alfalfa
• Almond
• Carrot
• Cotton
• Orange
• Peach and nectarine
• Pistachio
• Processing tomato
• Rice
• Strawberry
• Table and raisin grape
• Walnut
• Wine grape
• Appendix

How to Access the Summary of Pesticide Use Report Data

The Summary of Pesticide Use Report Data issued by the California Department of Pesticide Regulation (DPR) for the years 1989-2017 can be found by clicking the "Access Annual Reports" link under the Pesticide Use Annual Summary Reports section at www.cdpr.ca.gov/docs/pur/purmain.htm or by requesting the report from PUR.Inquiry@cdpr.ca.gov if not available online. The tables in the Statewide Report and County Summary Reports list the pounds of active ingredient (AI) applied, the number of applications, and the number of acres or other unit treated. The data is available in two formats:

• Indexed by chemical: The report indexed by chemical shows all the commodities and sites in which a particular AI was applied.
• Indexed by commodity: The report indexed by commodity shows all the AIs that were applied to a particular commodity or site.

The following pesticide use report data can be downloaded from the Department's File Transfer Protocol (FTP) site at https://files.cdpr.ca.gov/pub/outgoing/pur_archives/.

• Annual Report Data: The raw data used in the Pesticide Use Annual Summary Reports for 1989 to 2017. The files are in text (comma-delimited) format and do not include updates that occur after the Pesticide Use Annual Summary for that year was released. For updated data, use the online California Information Portal (CalPIP) at https://calpip.cdpr.ca.gov/main.cfm or contact DPR at PUR.Inquiry@cdpr.ca.gov
• Pesticide Use Data 1974 - 1989: Pesticide use data from 1974 to 1989 vary in the type and quality of data collected and are kept in a separate database. They are available as text files.
• Microfiche Pesticide Use Data 1970 - 1973: Files of summarized pesticide use data from 1970 to 1973 are available as PDF scans of microfiche.

Starting in 2016, the data from each figure or table in the annual report can be found at https://files.cdpr.ca.gov/pub/outgoing/pur/data/.

Please direct any questions regarding the Summary of Pesticide Use Report Data to the Department of Pesticide Regulation, Pest Management and Licensing Branch, P.O. Box 4015, Sacramento, California 95812-4015, or you may request copies of the data by contacting PUR.Inquiry@cdpr.ca.gov.

Year in Summary

Overview: Reported pesticide use for California in 2017 totaled 205 million pounds of applied active ingredients (AIs) and 104 million cumulative acres treated. Since 2016, pounds of AIs decreased by just over four million (2.0 percent) while the acres treated increased by around 3.4 million (3.3 percent). It is not unusual for trends in pounds and trends in acres treated - two common measures of pesticide use - to move in different directions, with an increase in one measure and a decrease in the other. "Pounds" is a pesticide use measure that tends to be driven by pesticides with large application rates, such as sulfur or fumigants, while cumulative "acres treated" is not influenced by application rates, focusing more on widespread use weighted by number of applications. Both measures taken together give a more nuanced understanding of how pesticide use changes over time.

Biopesticides, which have been identified as likely to be low risk to human health and the environment, increased in both the pounds applied and the acres treated in 2017. Similar to biopesticides, the acres treated with petroleum and mineral oils also increased, although the total pounds decreased. Most oil pesticides used in California serve as alternatives to more toxic pesticides. Some highly refined petroleum-based oils are used by organic growers.

Pounds of pesticides considered to be reproductive toxins, carcinogens, cholinesterase inhibitors, groundwater contaminants, toxic air contaminants, and fumigants all decreased in 2017. The acres treated with carcinogens, toxic air contaminants, and fumigants decreased as well.

The AIs with the highest total reported pounds were sulfur, petroleum and mineral oils, 1,3-dichloropropene, glyphosate, and metam-potassium (potassium N-methyldithiocarbamate) while the AIs with the highest reported cumulative acres treated were glyphosate, sulfur, petroleum and mineral oils, abamectin, and copper.

1. Introduction

History of pesticide use reporting in California

In the early 1880s, California passed legislation allowing counties to appoint horticultural commissioners to assist with pest management. These horticultural advisors were the forerunners of present-day County Agricultural Commissioners (CACs). During that early time period, many of these commissioners required agricultural pest control operators to submit some type of monthly report of pesticide use; however the exact requirements varied depending on the county. Most reports included details such as the location, date, crop, acres treated, pest, pesticide, and use rate. Unfortunately, many of these detailed records have been lost over time.

One of the first state-wide pesticide regulations was enacted in 1901. California passed a pesticide regulation law requiring product samples of Paris Green, an arsenic-based insecticide, to be submitted to University of California agricultural experiment stations in an effort to prevent consumer fraud from mislabeled and adulterated products. In 1911, California's State Insecticide and Fungicide Act furthered these protections by requiring labels identifying the component chemical amounts and information about the manufacturers.

In 1919, the California Department of Agriculture (CDA), now known as the California Department of Food and Agriculture (CDFA), was formed and began enforcing statewide pesticide laws. In 1921, the Economic Poisons Act was passed, giving the CDA the ability to regulate the manufacture, sale, and use of pesticides. From 1934 to 1956, the CDA produced a monthly Bulletin Report which included a summary pesticide use table. Starting in the early 1930s, the CDA began collecting statistics on aerial pesticide applications from the counties. In 1954, state regulators began requiring reports on ground application acreage as well, although these reports lacked detailed information about the pesticides used or commodities treated.

The 1960s brought increasing awareness about non-target effects of pesticides on the environment. At the federal level, congress passed numerous environmental statutes touching on pesticide regulation such as the Clean Water Act, the Clean Air Act, the Endangered Species Act, and the Occupational Safety and Health Act. In 1970, the U.S. EPA was created, taking over pesticide registration and residue tolerance functions from the U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA). In addition, the 1910 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was overhauled with a stronger focus on protecting human health and the environment.

California also expanded many of its regulations during this time period, surpassing the requirements called for by FIFRA and other federal regulations. In 1970, pesticide use reporting requirements broadened to include all pesticide applications by pest control operators (PCOs) as well as all restricted pesticide applications by growers. In the 1990s, the California Environmental Protection Agency (CalEPA) was founded. As part of CalEPA, the California Department of Pesticide Regulation (DPR) took over many pesticide regulatory roles, with exceptions such as pesticide residue laboratory testing, which remained with CDFA, and local enforcement authority, which remained with the counties.

The Food Safety Act of 1989 (Chapter 1200, AB 2161) gave DPR statutory authority to require full reporting of agricultural pesticide use, which officially began in 1990. Full-use reporting required more detail than ever before about a wider variety of pesticide applications than previous requirements. The first years of full-use reporting nearly overwhelmed DPR's capacity to process data. Use reports were on paper, and required staff to manually enter data from more than a million records each year. DPR began searching almost immediately for ways to automate reporting from pesticide users to the CAC, and, in turn, from the counties to DPR. However, it was difficult to find an approach that suited the diversity of use reporting and differing budget resources among the counties. Starting in 1991, various automated programs were developed and modified by DPR and CACs. Meanwhile, technological progress and increasing use of online resources by businesses fed expectations for more web-based functionality for pesticide use reporting. CalAgPermits was developed in 2011 to meet these needs, and is still in use today (See CalAgPermits, p. 6).

California's broad definition of "agricultural use" requires reporting pesticide applications in production agriculture, parks, golf courses, cemeteries, rangeland, pastures, and along roadside and railroad rights-of-way. Production agricultural pesticide use is a subset of agricultural use, defined as use of a pesticide for the "production for sale of an agricultural commodity" or "agricultural plant commodity." Each application of pesticide on crops (production agriculture) must include the site name given to a location or field by the CAC as well as the one by one square mile section in which the application occurred. Most other uses are aggregated and reported by month with only the county identified. These other uses include rights-of-way applications, all postharvest pesticide treatments of agricultural commodities, structural applications by licensed applicators, all pesticide treatments in poultry and fish production, and some livestock applications. In addition, all applications made by licensed applicators and outdoor applications of pesticides that have the potential to pollute groundwater must be reported. The primary exceptions to the reporting requirements are residential home and garden uses, veterinary uses, and most industrial and institutional uses.

In addition to requiring pesticide use reporting, California law (Food and Agricultural Code [FAC] section 12979) directs DPR to use the reports in setting priorities for monitoring food, enforcing pesticide laws, protecting the safety of farm workers, monitoring the environment for unanticipated residues, researching pest management practices, monitoring and researching public health issues, and similar activities. These activities help DPR with implementing another mandated activity: the continuous evaluation of currently registered pesticides (FAC section 12824). Information gathered during continuous evaluation is used to gauge the performance of DPR's regulatory programs and justify additional measures, including development of new regulations or reevaluation or cancellation of pesticide registrations. California Code of Regulations Title 3, sections 6624 et seq. further describe pesticide use record keeping and reporting requirements.

Continuous Evaluation of Pesticides

The Pesticide Use Report (PUR) greatly increases the accuracy and efficiency of continuous evaluation of pesticides by providing details on each application, including date, location, site (e.g., crop), time, acres and units treated, and the identity and quantity of each pesticide product applied. These data allow scientists and others to identify trends in pesticide use, compare use locations with other geographical information and data, and perform quantitative assessments and evaluations of risks that pesticides may pose to human health and the environment. Prior to full reporting, the regulatory program's estimates of pesticide use frequently relied on maximum rates and applications as listed on the label, potentially overstating many risks. Use of the PUR data allowed for much more accurate risk assessments and effective policy decisions. Over the years, these data have been used by a variety of individuals and groups, including government officials, scientists, growers, legislators, and public interest groups.

DPR uses the PUR throughout its pesticide regulatory programs in ways that can be broadly grouped as temporal (time), geospatial (place), and quantitative (amount), often combining elements of each.

Temporal analyses can pinpoint specific applications or span many years. Investigations into suspected worker illnesses, spray drift, fish or wildlife losses, or other enforcement inquiries frequently begin with a review of the PUR to see what applications were made in an area at a particular time. Protection of ground and surface waters, assessments of acute and chronic risks to human health, and allocation of monitoring and enforcement resources often include analyses of PUR data from numerous years to better evaluate pesticide use trends.

Geospatial analyses may be local or expansive. Local analyses are used to help set priorities for surface and groundwater monitoring programs by determining pesticide use and runoff potential in specific watersheds or other defined areas. DPR scientists calculate contributions of smog-forming volatile organic compounds (VOCs) in the atmosphere from pesticide products using pesticide use data in combination with emissions potential data of products. DPR further refines the analyses to specific air basins that are particularly vulnerable to air pollution to determine whether pesticide-related VOC emissions are below required targets or whether additional restrictions on use may be warranted to protect air quality. More expansive analyses examine the proximity of pesticide use to endangered species habitat, resulting in the development of best use practices to protect these species. These analyses are invaluable when assessing regulatory responses or evaluating the performance of voluntary stewardship efforts.

Quantitative assessments are broadly used to model risks of pesticide use to humans and the environment. The quality and depth of the information provided in the PUR allows researchers to apply realistic assumptions when modeling pesticide exposure. PUR data have been used to model pesticide exposure of people who live near agricultural lands, workers in the field, handlers preparing and applying pesticides, and aquatic organisms inhabiting waterways that receive agricultural runoff. Analysis of the PUR enables well-informed and realistic assessments for risk management decisions.

It is frequently assumed that increases in the pounds, acres treated, or number of applications of pesticides will correspond to higher risk to human health or the environment. However it is important to remember that risk is a function not only of the pesticide amount used, but also the toxicity of the AI to a non-targeted organism and the organism's exposure to the AI. For example, kaolin clay was a large contributor to the total pounds of pesticides used in California in 2017, ranking 11th in the top 100 pesticides used by pounds. Although many pounds of kaolin were used during the year, kaolin is a biopesticide and considered a minimum risk chemical. Increased use of lower risk chemicals do not heighten environmental or health risks in the same way as increased use of many conventional chemicals, and may actually serve to reduce overall risk if they are used as alternatives to higher risk chemicals.

In contrast, some AIs with high toxicity are only needed in very small amounts to be effective pest control agents, and therefore have low total pounds. However, if the toxicity, mode of action, and broad spectrum nature of the AI can cause unintended harm to a non-target organism, then a small amount of an AI with high toxicity could pose a greater risk than a large amount of an AI with a lower toxicity.

In addition to toxicity, exposure plays a large role in determining potential human health or environmental risks. Minimizing exposure to an AI is generally thought to reduce risk of harm from the AI. Risk can therefore be mitigated through a number of tools and practices that minimize exposure, such as personal protective equipment (PPE), buffer zones, drift reduction practices and equipment, application timing with favorable environmental conditions to prevent off-site pesticide movement, vegetative filter strips, tailwater ponds, and many other innovative techniques. In summary, when using PUR data to assess risk from an AI, its toxicity and exposure potential should be considered in relation to the amounts of pesticide used.

The passage of the federal Food Quality Protection Act (FQPA) of 1996 launched the PUR into a more integral role as a tool for monitoring and achieving compliance with updated food safety regulations. The FQPA contained a new food safety standard against which all pesticide tolerances – amounts of pesticide residue allowed by federal law to remain on a harvested crop – must be measured. PUR data became increasingly important to commodity groups, University of California (UC) specialists, the U.S. EPA, and other interested parties as they reassessed tolerances and calculated dietary risks from pesticides based on actual reported uses.

PUR information such as pesticide types, use rates, geographical locations, crops, and timing of applications help researchers understand how various pest management options are implemented in the field. Analyses of these data are the basis for grant projects that DPR funds to promote the development and adoption of integrated pest management practices in both agricultural and urban settings.

The PUR data are used by state, regional, and local agencies, scientists, and public interest groups. The data are an invaluable tool for understanding pesticide use in order to protect human health and the environment while balancing the population's need for quality food, fiber, shelter, and surroundings.

CalAgPermits

In 2011, the counties implemented CalAgPermits, a standardized, web-based system that greatly enhanced the efficiency of data entry and transfer, and thus the accuracy and integrity of the PUR database. In addition to helping CACs issue restricted-materials permits, it allowed individuals and businesses the option of reporting pesticide use electronically. The use of CalAgPermits also greatly enhanced data quality assurance by adding another level of automated data validation and error checking of submitted pesticide use reports in addition to what occurs after transmission to DPR.

The many improvements in the ability to share data electronically between DPR and CACs have greatly improved the efficiency and effectiveness of quality control for the PUR. Over the years, these data have been used by a variety of individuals and groups, including government officials, scientists, growers, legislators, and public interest groups.

Data Collection

Most pesticide use data required to be reported must be sent to the CAC in the county where the application took place. PURs can be submitted to the counties through individual CalAgPermit accounts, paper forms, or through third party software programs. After being sent to the CAC, the PUR is entered into the county CalAgPermit database and checked for a number of errors. The CAC then electronically sends required data to DPR, where additional validation and error checks take place. On average, DPR collects around three million pesticide use records a year. Currently the PUR database contains over 80 million pesticide use records, going back to 1990 (Earlier PUR records from 1974 to 1989 are kept in a separate database since these early records vary in the type and quality of data collected. PDF documents of scanned microfiche of pesticide records from 1970 to 1973 are also available).

Improving Data Quality

DPR checks the quality of PUR data many times between the initial data entry and before it is made available to the public. CalAgPermits checks for data entry errors, such as whether the pesticide applicator has the correct permits for any restricted materials reported or whether the pesticide product is allowed on the reported application site. Once the data have been received by DPR they undergo more than 50 different validity checks such as verifying product registration numbers and confirming that products are registered for use on the reported application site. The PUR database may include products that do not have an active registration since end-users are allowed to continue using stocks purchased prior to a product's registration becoming inactive. Records flagged for suspected errors are returned electronically to the county for resolution. If an error cannot be resolved, the record is transmitted to the database, but is logged as an error or outlier in a separate table, which is publically available.

Additional data checks are performed to identify errors and outliers in pesticide use amounts. These checks are conducted via a complex, automated, statistical procedure that was originally developed by DPR in the late 1990s, and has continually been improved over time. If a reported use rate (amount of pesticide per acres treated) greatly exceeds typical use rates of that AI, it is flagged as an error and sent back to the CAC to confirm. If the county is unable to identify the correct rate, an estimated rate equal to the median rate of all other applications of the pesticide product on the same crop or site is used instead. Although less than one percent of the reports are flagged with this type of error, some errors are so large that if included, they would significantly affect the total cumulative amount of applied pesticides. For more information on errors and identifying outliers in the PUR, see www.cdpr.ca.gov/docs/pur/outlier.pdf.

Non-production-agricultural PUR records are difficult to statistically evaluate for errors due to the lack of information on the acres treated. Current regulations do not require reporting this information. While statistical algorithms can analyze whether the amount of pesticide used over a given number of acres seems to be a reasonable application rate for production-agricultural PUR records, the lack of an acres treated value creates problems for catching errors in non-production-agricultural PURs. For many of these non-production-agricultural PURs, a rate is calculated as the amount of pesticide per application rather than per acres. These rates are statistically evaluated against similar applications for validity, alongside algorithms that check the total amounts against very high threshold values.

While the statistical algorithm currently in place detects many outliers in production agricultural pesticide use reports, its use for most structural pesticide applications is limited. In 2015, structural pesticide applicators were no longer required to report the number of applications. In addition, prior to 2015, there was a lot of variability in how the number of applications was interpreted, and reported, by the applicator. As a result, algorithms triggering errors when pesticide amounts are above high threshold values are used in conjunction with the statistical algorithms in an effort to catch very large errors. In addition, there has been a concerted effort by many DPR staff to manually identify exceptionally high structural PUR amounts and contact the applicators for verification - in many cases, these high amounts were mistakenly entered due to a misunderstanding that DPR wanted the diluted amount of pesticide rather than the undiluted amount. Many of these incorrect PURs have since been replaced by the correct, undiluted amounts. Future plans to further reduce errors in structural PURs include electronic warning flags that will notify CalAgPermit account holders if they enter an extremely high value, and remind them that undiluted amounts should always be reported.

Improving Access to the Data

There are several ways to access the PUR data. Annual reports serve as an accessible snapshot summary of the much larger PUR database. Before the late 1990s, summaries were available by request and were only hard copy. As use of online resources increased, DPR improved public access to the data by posting summary annually on its website www.cdpr.ca.gov/docs/pur/purmain.htm (Contact PUR.Inquiry@cdpr.ca.gov to request summaries from years not available online). In addition, the PUR data used in each annual report from 1984 on can be downloaded using DPR's File Transfer Protocol (FTP) website https://files.cdpr.ca.gov/pub/outgoing/pur_archives/. Data obtained from the FTP site does not include updates that may have occurred after the release of the annual report. Scans of the hard copy summaries from 1974 to 1989 are also available on the FTP site and are primarily a tabular summary of pesticide use data by county. Current annual reports are more detailed and analyze various pesticide use trends. In 2016, PDF files of scanned summary pesticide use reports on microfiche from 1970 to 1973 were added to the FTP site for download.

Starting in 1996, DPR scientists began analyzing critical crops and their pest problems as well as trends in the pounds of pesticides used, and the number of applications and acres treated. Each year, the annual report charts pesticide use over several years in specific categories:

• Reproductive toxins
• Carcinogens
• Organophosphorus and carbamate cholinesterase inhibitors
• Chemicals classified by DPR as groundwater contaminants
• Chemicals listed by DPR as toxic air contaminants
• Fumigants
• Oil pesticides derived from petroleum distillation (many of which serve as alternatives to high-toxicity pesticides)
• Biopesticides (including biochemical pesticides that control pests by non-toxic mechanisms (for example, pheromones and bait attractants) and microbial pesticides. Biopesticides are considered to be less toxic and more selective than conventional pesticides)
• Crops (DPR analyzes pesticide use trends for around a dozen crops with the highest amount of pesticide used or acreage treated)

Pesticide use trend analyses can help regulatory agencies evaluate the success of their efforts to promote reduced-risk pest management strategies. Information on long-term trends also helps researchers better identify emerging challenges and direct research to finding solutions.

In 2003, DPR launched the web-based California Pesticide Information Portal (CalPIP) to increase public access to the PUR database. CalPIP provides pesticide use information including date, site or crop treated, pounds used, acres treated, pesticide product name, AI name, application pattern (ground, air, or other), county, ZIP code, and location where the application was made to within a one-square-mile area. DPR annually updates the previous few years of CalPIP data to account for any changes due to errors identified after the annual report has been released, so it is the most up-to-date source of pesticide information available via the main PUR website www.cdpr.ca.gov/docs/pur/purmain.htm. Starting in 2016, text files of the data from all tables and figures in the annual reports can be accessed at https://files.cdpr.ca.gov/pub/outgoing/pur/data/.

2. Comments and Clarifications of Data

When analyzing the data contained in this report, it is important to consider the following:

Terminology

• Product versus active ingredient (AI): A pesticide product contains both active and inert ingredients. An AI is a component of a pesticide product that controls target pests. There can be more than one AI in a product. Inert ingredients are all the other ingredients of the product which do not target the pest but may enhance product performance and application. Specific products are reported in the pesticide use reports submitted to DPR. DPR identifies the AIs of these products for trend analysis.
• Number of agricultural applications: Number of applications of pesticide products made to production agriculture. More detailed information is given below under "Number of Applications."
• Pounds applied: Total pounds of active ingredient summed over a given time period, geographic area, crop, or other category of interest. The pounds of AI in a single application is calculated by converting the product amount to pounds, then multiplying the pounds of product by the percent of the AI in the product.
• Unit type: The type of area treated with the pesticide
  • A = Acreage
  • C = Cubic feet (usually of postharvest commodity treated)
  • K = Thousand cubic feet (usually of postharvest commodity treated)
  • P = Pounds (usually of postharvest commodity treated)
  • S = Square feet
  • T = Tons (usually of postharvest commodity treated)
  • U = Miscellaneous units (e.g., number of tractors, trees, tree holes, bins)
• Acres treated: Cumulative number of acres treated. More detailed information is given below under "Acres Treated."
• Risk Analysis: When using PUR data to analyze potential human health or environmental risks, the toxicity of the AI and the potential for exposure, in addition to the amount of pesticide used, should always be considered.

Agricultural and Non-Agricultural Pesticide Use

Many pesticide licensing, sales, and use requirements are tied to California's definition of agricultural use. Pesticide labels differentiate between agricultural, industrial, or institutional uses. Some pesticide products are labeled for both agricultural and nonagricultural uses.

California law (FAC section 11408) identifies agricultural use as all use except the following categories specifically identified as nonagricultural use:

• Home: Use in or around the immediate environment of a household. Licensed, professional pesticide applications are reported as nonagricultural use (usually "structural pest control" or "landscape maintenance"). Unlicensed, non-professional, residential pesticide applications around a home or garden are not required to be reported.
• Industrial: Use in or on property necessary to operate factories, processing plants, packing houses, or similar buildings or use for a manufacturing, mining, or chemical process. Postharvest commodity fumigations in buildings or on trucks, vans, or rail cars are normally considered industrial use. Industrial pesticide uses are not required to be reported unless the pesticide is a restricted material, has the potential to pollute groundwater, or was applied by a licensed pest control operator. In California, industrial use does not include use on rights-of-way.
• Institutional: Use in or on property necessary to operate buildings such as hospitals, office buildings, libraries, auditoriums, or schools. Includes pesticide use on landscaping and around walkways, parking lots, and other areas bordering the institutional buildings. Institutional pesticide uses are not required to be reported unless the pesticide is a restricted material, has the potential to pollute groundwater, or was applied by a licensed pest control operator. Note that the Healthy Schools Act of 2000 imposes additional pesticide use reporting requirements if the pesticide application takes place at a school or childcare center, regardless of whether or not the application was made by a licensed professional.
• Structural: Use by licensed structural pest control operators within the scope of their licenses
• Vector control: Use by certain vector control (e.g., mosquito abatement) districts
• Veterinary: Use according to a written prescription of a licensed veterinarian. Veterinary prescription pesticide use is not reported to the State.

Agricultural use of pesticides includes:

• Production agricultural use: Any pesticide used to produce a plant or animal agricultural product (food, feed, fiber, ornamental, or forest) that will be distributed in the channels of trade (Some requirements most notably those that address worker safety and use reporting apply only to plant product production.)
• I: Any pesticide used on watersheds, rights-of-way, and landscaped areas (e.g., golf courses, parks, recreation areas, and cemeteries) not covered by the definitions of home and institutional uses

The following specific pesticide uses are required to be reported to the CAC who, in turn, reports the data to DPR:

• Production of any agricultural commodity except livestock (where livestock is defined in FAC section 18663 as "any cattle, sheep, swine, goat, or any horse, mule or other equine, whether live or dead")
• Treatment of postharvest agricultural commodities
• Landscape maintenance in parks, golf courses, cemeteries, and similar sites defined in the FAC as agricultural use
• Roadside and railroad rights-of-way
• Poultry and fish production
• Application of a restricted material
• Application of a pesticide listed in regulation as having the potential to pollute ground water when used outdoors in industrial and institutional settings
• Application by licensed pest control operators, including agricultural and structural applicators and maintenance gardeners

Growers must submit their production agricultural pesticide use reports to the CAC by the tenth day of the month following the month in which the work was performed, and pest control businesses must submit seven days after the application. Not all information submitted to the counties is transferred to DPR.

What must be reported.

Production agricultural pesticide use reports include the following:

• Date and time of application
• Geographic location including the county, meridian, township, range, and section
• Operator identification number or permit number (An operator identification number or permit number is issued by CAC to property operators. These numbers are needed to report pesticide use and, for permit numbers, to purchase restricted-use pesticides. DPR combines the reporting county code, the application year, the home county code, and the operator ID or permit number to form a data field called the "Grower ID" )
• Operator name and address (this information is not submitted to DPR)
• Site identification number (A site identification code must be assigned to each location or field where pesticides will be used for production of an agricultural commodity. This alphanumeric code is also recorded on any restricted material permit the grower obtains for the location.)
• Commodity, crop, or site treated
• Acres planted and treated (Not required for most nonagricultural PURs)
• Application method (e.g., by air, ground, or other means)
• Fumigation methods. Since 2008, fumigation applications in nonattainment areas that do not meet federal air quality standards for pesticide VOC emissions must be identified along with details on fumigation methods (for example, shallow shank injection with a tarp). This information allows DPR to estimate pesticide VOC emissions, which contribute to the formation of atmospheric ozone, an important air pollutant.
• Product name, U.S. EPA Registration Number (or the California Registration Number if the product is an adjuvant), and the amount of product applied

All other kinds of pesticide use (mostly nonagricultural) are reported as monthly summaries that include the following information:

• Pesticide product name
• Product registration number
• Amount used of product over entire month
• Number of applications (except for structural applications, which were exempted from reporting number of applications in 2015)
• Application site (e.g., rights-of-way, structural)
• Month of application (rather than date and time)
• County (rather than square mile section location)

Site Codes

The site code refers to the site, commodity, or crop of the pesticide application. It is often referred to as the commodity code, although there are nonagricultural codes as well, such as a structural site code used for pesticide applications to buildings and other structures. DPR uses its product label database (www.cdpr.ca.gov/docs/label/labelque.htm) to verify that products listed in pesticide use reports are registered for use on the reported site. The product label database uses a coding system consistent with U.S. EPA official label information. To minimize errors, DPR developed a cross-reference table to link the different site code naming systems of the U.S. EPA, DPR's product label database, and the PUR database.

Certain commodities or sites may have more than one associated site code if different production methods or uses of the commodity result in different pesticide use. For example, greenhouse and nursery operations are divided into six different site codes: greenhouse-grown cut flowers or greens, outdoor-grown cut flowers or greens, greenhouse-grown plants in containers, outdoor-grown plants in container/field-grown plants, greenhouse-grown transplants/propagative material, and outdoor-grown transplants/propagative material.

Tomatoes and grapes are also separated into further subcategories because of public and processor interest in differentiating pesticide use. Tomatoes are assigned codes to differentiate between fresh market and processing categories. Grapes are assigned separate codes to differentiate table grapes and raisins from wine grapes.

Unregistered Use

The PUR database may contain records of pesticide use on a commodity or site for which the pesticide is not currently registered. Unregistered uses that are not detected by the error-checking process may be due to an error in the DPR product label database, where the product incorrectly lists a commodity or site as being registered. Other unregistered uses may be flagged as errors by the validation procedures, but left unchanged in the database. The error-checking process does not check whether the product was registered at the time of application. It is therefore possible that an application flagged as an error due to a recent change in registration may have been legally applied at the time of application. In addition, the law sometimes allows the use of existing stocks of a pesticide product following its withdrawal from the market by the manufacturer, or suspension or cancellation by regulatory authorities, since the safest way to dispose of small quantities of pesticides is often to use them as they were intended. Finally, some pesticide products do not list specific sites or commodities on their labels as they are designed to target specific pests across all sites, such as some soil fumigants, certain pre-plant herbicides, and rodenticides. In these cases, reporting an application of one of these types of pesticides on a specific commodity or site can result in an error. In 2015, an option was added in CalAgPermits that allows the user to designate any application as "pre-plant" and enter the commodity or site without generating any error messages.

Adjuvants

Use data on spray adjuvants (e.g., emulsifiers, wetting agents, foam suppressants, and other efficacy enhancers) were not reported before full-use reporting was required. Adjuvants are exempt from federal registration requirements but must be registered as pesticides in California. Examples of adjuvants include many alkyl groups and some petroleum distillates. Adjuvant product formulations are considered proprietary and are therefore confidential, however pesticide use totals for adjuvant AIs are included in the annual report.

Cumulative Acres Treated

The cumulative acres treated is the sum of the acres treated with an AI and is expressed in acres (applications reported in square feet are converted to acres). The cumulative acres treated for a crop may be greater than the planted acres of the crop since this measure accounts for a field being treated with the same AI more than once in a year. For example, if a 20-acre field is treated three times in a calendar year with an AI, the cumulative acres treated would be reported as 60 acres while the acres planted would be reported as 20 acres.

It is important, however, to be aware of the potential to over-count acreage when summing cumulative acres for products that have more than one AI. If a 20-acre field is treated with a product that contains three different pesticide AIs, the PUR record will correctly show that the product was applied to 20 acres, but that 20 acre value will also be attributed to each of the three AIs in any chemical summary reports. Adding these values across the AIs results in a total of 60 acres treated instead of the 20 acres actually treated. For more information on over-counting pesticide use data, see Over-counting Pesticide Use

Number of Applications

The number of applications is only included in the Annual Summary Report for production agricultural applications. Applicators are required to submit one of two basic types of use reports, a production agricultural report or a monthly summary report. The production agricultural report must include information for each application. The monthly summary report, required for all uses other than production agriculture, includes only monthly totals for all applications of pesticide product, site or commodity, and applicator.

The total number of applications in the monthly summary reports is not consistently reported, so they are no longer included in the annual totals. (In the annual PUR reports before 1997, each monthly summary record was counted as one application). On January 1, 2015, an amendment to section 8505.17 of the Business and Professions Code (BPC) brought about by the passage of Senate Bill 1244 (Chapter 560, Statutes of 2014), eliminated the requirement to report the number of applications made in monthly summary structural PURs.

Note that in the annual summary report arranged by commodity, the total number of agricultural applications for the site or commodity may not equal the sum of all applications of the listed AIs. Since the summary report is at the AI level rather than the product level, a single application of a product comprised of two AIs will result in the summary report assigning the single application to both AIs listed under the commodity heading. Summing the agricultural applications for these two AIs would result in an incorrect total of two applications. The total applications value at the bottom of each commodity section removes the possibility of over-counting applications for products with more than one AI, and is therefore a more accurate value. For more information on over-counting pesticide use data, see the following section, Over-counting Pesticide Use

Over-counting Pesticide Use

PUR data is available to the public, and is often used in various types of analyses (See section on How to Access the Summary of Pesticide Use Report Data. Recall that pesticide products may be composed of one or more AIs (plus any confidential inert ingredients). The PUR database includes a wide assortment of information related to both the product and the AI. Different types of analyses will use different subsets of information on the product, the AI, or both. Depending on the data subset chosen for analysis, one can unintentionally over-count pesticide use if the following three criteria are all true:

• Criteria 1: The chosen subset of PUR data includes products with more than one AI.
• Criteria 2: The chosen subset of PUR data includes both product and AI information.
• Criteria 3: The analysis sums treated or planted acres, pounds or amount of product, or number of applications.

The following two examples show two different hypothetical pesticide use analyses of a fictitious product, "Generic Bug Killer," which has two AIs: chem1 and chem2. Both analyses sum pesticide use variables for the same three fictitious PUR records, however they use slightly different subsets of information from the PUR database. The second example over-counts certain pesticide use variables.

The first example (Table 1) does not meet all three criteria listed above, so does not over-count pesticide use. Although Table 1 has PUR data for a product with two AIs (criteria 1) and is summing acres, product pounds, and applications (criteria 3), it does not include any information about chem1 and chem2, the two AIs (criteria 2). Since the second criteria is not met, the sums of acres treated ("Acres"), pounds of product ("Lbs Prod"), and number of applications ("Apps") are correct.

Table 1: Example of three PUR records for a fictitious product (Generic Bug Killer) with two AIs. Summing acres treated (Acres), product amount (Lbs Prod), or number of applications (Apps) from this table would be correct since the table does not contain AI information.

In the second example (Table 2), there are two additional columns: the AI name ("AI") and the pounds of AI ("Lbs AI"). The addition of AI information satisfies criteria 2. Now all three criteria are fulfilled and over-counting becomes an issue for acres treated, pounds of product, and number of applications. Although Table 2 shows the same three PUR records as Table 1 (as identified by unique year - use number ("Use no") combinations), there are now six table rows instead of three: each PUR record has a row for each of the two AIs, chem1 and chem2. The values for Year, Use no, Product, Acres, Units, Lbs Prod, and Apps are repeated on both rows of each PUR record. Summing acres treated ("Acres"), product amount ("Lbs Prod"), or number of applications ("Apps") from Table 2 now results in doubled amounts (The total pounds of AI ("Lbs AI"), however, is correct).

Table 2: Example of three PUR records for a fictitious product (Generic Bug Killer) with two AIs. Summing acres treated (Acres), product amount (Lbs Prod), or number of applications (Apps) from this table would be incorrect since the table contains AI information and the product has two AIs. Summing the pounds of AI (Lbs AI), however, is correct.

To avoid over-counting, it is important to identify individual PUR records by the unique combination of year and use number assigned to the record, and be aware of whether or not any data values are being repeated for PUR records that span multiple rows before performing any aggregations.

3. Data Summary

This report is a summary of 2017 data submitted to DPR as of August 10, 2018. PUR data are continually updated and therefore may not match later data from CalPIP or internal queries that contain corrected records identified after August 10, 2018.

Pesticide Use In California

In 2017, as in previous years, the region of greatest pesticide use was California's San Joaquin Valley (Table 3). The four counties in this region with the highest use were Fresno, Kern, Tulare, and San Joaquin. These counties were also among the leading producers of agricultural commodities.

Table 3: Total pounds of pesticide active ingredients reported in each county and their rank during 2016 and 2017. Text files of data are available.

Reported pesticide use in California in 2017 totaled 205 million pounds, a decrease of four million pounds (2.0 percent) from 2016. Much of the decrease occurred in production agriculture, where use declined by 3.7 million pounds (1.9 percent). Structural and landscape pesticide use also decreased, while postharvest treatments increased by 20 percent. Postharvest treatments are predominantly commodity fumigations, but can also include pesticide treatments to irrigation ditches and other parts of fields not planted in crops. The remaining assortment of nonagricultural pesticide uses decreased as a whole by about three percent. This group includes pesticide use for research purposes, vector control, pest and weed control on rights-of-way, and pest control through fumigation of non-food and non-feed materials such as lumber and furniture.

Table 4 breaks down the pounds of pesticide by general use categories: production agriculture, postharvest treatment, structural pest control, landscape maintenance, and all others.

Table 4: Pounds of pesticide active ingredients, 1998 – 2017, by general use categories. Text files of data are available.

4. Trends in Pesticide Use for Select Pesticide Categories

This report discusses three different measures of pesticide use: amount of AI applied in pounds, cumulative acres treated in acres (for an explanation of cumulative acres treated), and to a lesser degree, application counts. While most pesticides are applied at rates of one to two pounds per acre, some may be as low as a few ounces or as high as hundreds of pounds per acre. When comparing use among different AIs, pounds of use will emphasize pesticides used at high rates, such as sulfur, horticultural oils, and fumigants. In contrast, acres treated lacks the bias toward pesticides with higher application rates, identifying the pesticides used over the widest area. However acres treated is not always reported for non-production-agricultural pesticide use reports. Application counts can also be a useful measure of pesticide use, however it has been inconsistently reported for non-production-agricultural use and is no longer required for structural use reporting, so it is not included as often in the annual report.

The contrast between measuring pesticide use by pounds or by acres can be seen by looking at the use of different pesticide types (Figures 1 and 2). Figure 1, the amount applied by weight (pounds), shows that pesticides with both fungicidal and insecticidal properties (fungicide/insecticides) such as sulfur had the highest use in 2017. The fungicide/insecticide category was followed by insecticides, fumigants, herbicides, fungicides, and finally, "Other" types of pesticides, which grouped all remaining types of pesticides that did not have large enough amounts used to warrant their own graph trend line. ("Other" pesticides include rodenticides, molluscicides, algaecides, repellents, antimicrobials, antifoulants, disinfectants, and biocides). In contrast, by cumulative area (acres) treated in Figure 2, insecticides, herbicides, and fungicides had the highest use, followed by fungicide/insecticides, "Other", and, finally, fumigants. The trends in use for a single AI will usually follow similar patterns of increases or decreases for both pounds and acres treated measures of pesticide use. However, when looking at cumulative totals of many AIs over a period of time or a region, the trends may diverge depending on what measure of pesticide use is analyzed, with pounds increasing while acres treated decreases, or vice versa.

Figure 1, PNG: Pounds of all AIs in the major types of pesticides from 1997 to 2017, where "Other" includes pesticides such as rodenticides, molluscicides, algaecides, repellents, antimicrobials, antifoulants, disinfectants, and biocides. Text files of data are available.

Figure 2, PNG: Acres treated by all AIs in the major types of pesticides from 1997 to 2017, where "Other" includes pesticides such as rodenticides, molluscicides, algaecides, repellents, antimicrobials, antifoulants, disinfectants, and biocides. Text files of data are available.

There were 205 million pounds of pesticides used in 2017, a decrease of over four million pounds (2 percent) from 2016. The AIs with the highest total reported pounds were sulfur, petroleum and mineral oils, 1,3-dichloropropene, glyphosate, and metam-potassium (potassium N-methyldithiocarbamate). Sulfur accounted for 23 percent of total pesticide pounds in 2017.

Reported pesticide use by cumulative acres treated in 2017 was 104 million acres, an increase of 3.4 million acres (3.3 percent) from 2016. The non-adjuvant pesticides applied to the greatest area in 2017 were glyphosate, sulfur, petroleum and mineral oils, abamectin, and copper (Figures 3, 4, and appendix figure A-1). For insecticides, the top AIs by acres treated included petroleum and mineral oils, abamectin, lambda-cyhalothrin, chlorantraniliprole, and methoxyfenozide. For fungicides, the top five AIs were copper, followed by azoxystrobin, pyraclostrobin, fluopyram, and propiconazole. For AIs that could serve as either fungicides or insecticides, sulfur was by far the highest in acres treated, followed by petroleum and mineral oils, kaolin, lime-sulfur, and finally neem oil (Figure 3). Glyphosate topped the list for acres treated among herbicides, followed by oxyfluorfen, glufosinate-ammonium, paraquat dichloride, and pendimethalin. Fumigants had relatively low acres treated compared to other types of pesticides. 1,3-dichloropropene had the highest acres treated of the fumigants, just edging out aluminum phosphide for first place. Zinc phosphide, chloropicrin, and metam-potassium made up the remaining top five fumigants. The remaining "Other" category was largely comprised of plant growth regulators and harvest aids, with ethephon leading in acres treated, followed by gibberellins, mepiquat chloride, thidiazuron, and finally 2,4-D (when used as a harvest aid rather than an herbicide)(Figure 4).

Figure 3, PNG: Acres treated by the top five AIs in each of the major types of pesticides from 2011 to 2017. Text files of data are available.

Figure 4, PNG: Acres treated by the top five AIs in each of the major types of pesticides from 2011 to 2017. Text files of data are available.

Since 1990, the reported pounds of pesticides applied and acres treated have fluctuated from year to year. These fluctuations can be attributed to a variety of factors, including changes in planted acreage, crop plantings, pest pressures, and weather conditions. An increase or decrease in use from one year to the next or in the span of a few years may not necessarily indicate a general trend in use, but rather variations related to changes in weather, pricing, supply of raw ingredients, or regulations. Regression analyses on use over the last twenty years do not indicate a significant trend of either increase or decrease in total pesticide use.

Pesticide use is summarized for eight different pesticide categories from 2008 to 2017 (Tables 5 – 20) and from 1997 to 2017 (Figures 5 – 12). These categories include reproductive toxicity, carcinogens, cholinesterase inhibitors, groundwater contaminants, toxic air contaminants, fumigants, oils, and biopesticides. Changes from 2016 to 2017 are summarized as follows:

• Reproductive toxins: Chemicals classified as reproductive toxins decreased in amount applied from 2016 to 2017 (one million pound decrease, 12.0 percent) but increased in acres treated (280 thousand acres treated increase, 6.1 percent). The decrease in amount applied was mainly due to a decrease in use of the fumigants methyl bromide and metam-sodium. The increase in acres treated was largely due to higher use of abamectin, an AI that is used to control insects and mites. Pesticides in this category are listed on the State's Proposition 65 list of chemicals known to cause reproductive toxicity. Chlorpyrifos was added to the Proposition 65 list in 2017.
• Carcinogens: The amount of pesticides classified as carcinogens decreased by 2.5 million pounds from 2016 to 2017 (5.6 percent decrease), and the acres treated decreased by a little more than two thousand acres (0.03 percent). The decrease in amount applied was largely due to less use of the fumigants 1,3-dichloropropene, metam-sodium, and metam-potassium, as well as a decrease in the use of the herbicide glyphosate and the fungicide iprodione. The decrease in acres treated was mostly due to less use of glyphosate and iprodione. The pesticides in this category are listed by U.S. EPA as A or B carcinogens or on the State's Proposition 65 list of chemicals known to cause cancer. Glyphosate was added to the Proposition 65 list in 2017.
• Cholinesterase inhibitors: Use of organophosphorus and carbamate cholinesterase-inhibiting pesticides decreased from the previous year by 113,000 pounds (2.6 percent decrease) but increased by 57,000 acres treated (1.7 percent increase). Most of the decrease in amount applied resulted from a decrease in the use of the insecticides carbaryl, naled, methomyl, malathion, dimethoate, and bensulide and the herbicide thiobencarb. The increase in acres treated was largely due to a rise in use of the plant growth regulator ethephon and the insecticide chlorpyrifos.
• Groundwater contaminants: The use of AIs categorized as groundwater contaminants decreased in amount applied by 123,000 pounds (25.3 percent decrease) but increased in acres treated by 48,000 acres (10.1 percent increase), mainly from changes in the use of the herbicide diuron.
• Toxic air contaminants: The use of AIs categorized as toxic air contaminants decreased in amount applied by 2.9 million pounds (6.4 percent decrease) and decreased in acres treated by 159,000 acres (6.2 percent decrease). Decreases in the pounds of metam-potassium, metam-sodium, and 1,3-dichloropropene accounted for much of the overall decrease in amount applied. The decrease in acres treated was due to fewer acres treated with the herbicides 2,4-D, dimethylamine salt and trifluralin.
• Fumigants: The use of fumigant AIs decreased by 2.4 million pounds (5.8 percent decrease) and by 14,000 acres treated (4.6 percent decrease). Much of the decrease was due to less pounds applied of metam-potassium, metam-sodium, and 1,3-dichloropropene, and less acres treated with aluminum phosphide.
• Oils: Use of oil pesticides decreased in amount by 1.2 million pounds (3.1 percent decrease), and decreased in acres treated by 101,000 acres (1.9 percent decrease). Only oil AIs derived from petroleum distillation are included in these totals. Although some oils are listed on the State's Proposition 65 list of chemicals known to cause cancer, none of these carcinogenic oils are known to be used as pesticides in California. Most oil pesticides used in California serve as alternatives to more toxic pesticides. Some highly refined petroleum-based oils are used by organic growers.
• Biopesticides: Use of biopesticides and AIs considered to be lower risk to human health or the environment increased in amount by 422,000 pounds (5.5 percent increase) and by 522,000 acres (6.5 percent increase). The fungicide potassium phosphite and the adjuvant vegetable oil had the largest increases in both pounds and acres treated. In general, biopesticides are derived from natural materials such as animals, plants, bacteria, and minerals. In some cases they are synthetic mimics of these natural materials.

The summaries detailed above and the data presented in the following use category tables are not intended to serve as indicators of pesticide risks to the public or the environment. Rather, the data supports DPR regulatory functions to enhance public safety and environmental protection. (See "Continuous Evaluation of Pesticides" on page 4.)

USE TRENDS OF PESTICIDES ON THE STATE'S PROPOSITION 65 LIST OF CHEMICALS THAT ARE "KNOWN TO CAUSE REPRODUCTIVE TOXICITY."

Table 5: The reported pounds of pesticides used that are on the State's Proposition 65 list of chemicals that are "known to cause reproductive toxicity." Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 6: The reported cumulative acres treated with pesticides that are on the State's Proposition 65 list of chemicals that are "known to cause reproductive toxicity." Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 5, PNG: Use trends of pesticides that are on the State's Proposition 65 list of chemicals that are "known to cause reproductive toxicity." Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available.

USE TRENDS OF PESTICIDES LISTED BY U.S. EPA AS A OR B CARCINOGENS OR ON THE STATE'S PROPOSITION 65 LIST OF CHEMICALS THAT ARE "KNOWN TO CAUSE CANCER."

Table 7: The reported pounds of pesticides used that are listed by U.S. EPA as A or B carcinogens or on the State's Proposition 65 list of chemicals that are "known to cause cancer." Use includes both agricultural and reportable nonagricultural applications. Text files of data are available.

Table 8: The reported cumulative acres treated with pesticides that are listed by U.S. EPA as A or B carcinogens or on the State's Proposition 65 list of chemicals that are "known to cause cancer." Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available.

Figure 6, PNG: Use trends of pesticides that are listed by U.S. EPA as A or B carcinogens or on the State's Proposition 65 list of chemicals that are "known to cause cancer." Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF CHOLINESTERASE-INHIBITING PESTICIDES

Table 9: The reported pounds of pesticides used that are organophosphorus or carbamate cholinesterase-inhibiting pesticides. Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 10: The reported cumulative acres treated with pesticides that are organophosphorus or carbamate cholinesterase-inhibiting pesticides. Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 7, PNG: Use trends of pesticides that are organophosphorus or carbamate cholinesterase-inhibiting pesticides. Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF PESTICIDES ON THE "A" PART OF DPR'S GROUNDWATER PROTECTION LIST.

Table 11: The reported pounds of pesticides used that are on the "a" part of DPR's groundwater protection list. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6800(a). Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 12: The reported cumulative acres treated with pesticides that are on the "a" part of DPR's groundwater protection list. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6800(a). Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 8, PNG: Use trends of pesticides that are on the "a" part of DPR's groundwater protection list. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6800(a). Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF PESTICIDES ON DPR'S TOXIC AIR CONTAMINANTS LIST

Table 13: The reported pounds of pesticides used that are on DPR's toxic air contaminants list applied in California. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6860. Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 14: The reported cumulative acres treated with pesticides that are on DPR's toxic air contaminants list applied in California. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6860. Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 9, PNG: Use trends of pesticides that are on DPR's toxic air contaminants list applied in California. These pesticides are the active ingredients listed in the California Code of Regulations, Title 3, Division 6, Chapter 4, Subchapter 1, Article 1, Section 6860. Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF PESTICIDES THAT ARE FUMIGANTS

Table 15: The reported pounds of pesticides used that are fumigants. Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 16: The reported cumulative acres treated with pesticides that are fumigants. Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 10, PNG: Use trends of pesticides that are fumigants. Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF OIL PESTICIDES.

Table 17: The reported pounds of pesticides used that are oils. Although some oils and other petroleum distillates are on U.S. EPA's list of A or B carcinogens or the State's Proposition 65 list of chemicals "known to cause cancer," these carcinogenic oils are not known to be used in California as pesticides. Many oil pesticides used in California serve as alternatives to chemicals with higher toxicity. Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 18: The reported cumulative acres treated with pesticides that are oils. Although some oils and other petroleum distillates are on U.S. EPA's list of A or B carcinogens or the State's Proposition 65 list of chemicals "known to cause cancer," these carcinogenic oils are not known to be used in California as pesticides. Many oil pesticides used in California serve as alternatives to chemicals with higher toxicity. Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 11, PNG: Use trends of pesticides that are oils. Although some oils and other petroleum distillates are on U.S. EPA's list of A or B carcinogens or the State's Proposition 65 list of chemicals "known to cause cancer," these carcinogenic oils are not known to be used in California as pesticides. Many oil pesticides used in California serve as alternatives to chemicals with higher toxicity. Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

USE TRENDS OF BIOPESTICIDES

Table 19: The reported pounds of pesticides used that are biopesticides. Biopesticides include microorganisms and naturally occurring compounds, or compounds similar to those found in nature that are not toxic to the target pest (such as pheromones). Use includes both agricultural and reportable nonagricultural applications. Text files of data are available..

Table 20: The reported cumulative acres treated with pesticides that are biopesticides. Biopesticides include microorganisms and naturally occurring compounds, or compounds similar to those found in nature that are not toxic to the target pest (such as pheromones). Use includes primarily agricultural applications. The grand total for acres treated may be less than the sum of acres treated for all active ingredients because some products contain more than one active ingredient. Text files of data are available..

Figure 12, PNG: Use trends of pesticides that are biopesticides. Biopesticides include microorganisms and naturally occurring compounds, or compounds similar to those found in nature that are not toxic to the target pest (such as pheromones). Reported pounds of active ingredient (AI) applied include both agricultural and nonagricultural applications. The reported cumulative acres treated include primarily agricultural applications. Text files of data are available..

5. Trends In Pesticide Use for Select Commodities

A grower's or applicator's decision to apply pesticides depends on many factors, such as the presence of biological control agents (e.g., predatory insects and other natural enemies), current pest levels, cost of pesticides and labor, value of the crop, pesticide resistance and effectiveness, other available management practices, and potential pesticide risk to the environment or farm workers. Pest population and the resulting pest pressure is determined by complex ecological interactions. Weather is a critically important factor and affects different pest species in different ways. However, sometimes the causes of pest outbreaks are unknown.

Crops treated with the greatest total pounds of pesticides in 2017 were almond, wine grape, table and raisin grape, orange, and strawberry. Besides total pounds, the magnitudes of changes in use can be of interest in understanding pesticide use trends. Table 21 shows the change in pounds for ten crops (or sites): the first five rows are the crops with the greatest increases in pounds and the last five rows are the crops with the greatest decreases over the last year. In addition to the change in pounds of pesticide since last year, the table also includes the change in acres planted or harvested, as measured by external government agencies such as CDFA or USDA. Sometimes changes in use can be due to different pesticide practices, but other times the increase or decrease in use may simply be because the total crop acreage increased or decreased.

Crops or sites with the greatest increase in the pounds applied from 2016 to 2017 include wine grape, cotton, orange, walnut, and dried bean. Wine grape and orange had increases in pesticide use despite decreases in acreage. Cotton and walnut both increased in acreage as well as pesticide use. Dried bean increased in pesticide use, but acreage remained constant (Table 21).

Crops or sites with the greatest decrease in the pounds applied include processing tomato, almond, rice, soil fumigation/preplant, and grape. Processing tomato, rice, and table and raisin grape had decreasing pounds of pesticides accompanied by declining acreage, whereas pounds applied to almonds decreased despite an increase in acreage (Table 21). The large decrease in pounds attributed to the soil fumigation/preplant site may be due in part to a relatively new (circa 2015) preplant box available when submitting pesticide use reports. When the preplant box is checked on the pesticide use report form, the specific crop to be planted afterward into the fumigated soil, if known, can be listed as the site of the fumigation application. This new preplant box option allows these types of preplant pesticide applications to be associated with specific crops, which is useful for more accurate pesticide trend analyses. However as the preplant box is increasingly adopted over time, it may create the appearance of a decreasing trend of pesticide use under the soil fumigation/preplant site (and a corresponding increasing use trend under the various crops or sites that the pesticide application is now listed under) due to the change in reporting rather than an actual change in pesticide use.

Table 21: The change in pounds of AI applied and acres planted or harvested and the percent change from 2016 to 2017 for the crops or sites with the greatest increase and decrease in pounds applied. Acre values sourced from CDFA (a,b), USDA(a,b,d), and CCTGA.

Thirteen commodities were chosen for in-depth analyses of the possible reasons for changes in pesticide use from 2016 to 2017: alfalfa, almond, carrot, cotton, orange, peach and nectarine, pistachio, processing tomato, rice, strawberry, table and raisin grape, walnut, and wine grape. (Peach and nectarine' and table and raisin grapes' each contain two crops, grouped together for the purposes of the annual report due to similar pesticide use). They were selected because each commodity was treated with more than four million pounds of AIs or had more than three million acres treated, cumulatively. Collectively, the pesticides used on these commodities represent 72 percent of the total amount used (pounds) and 75 percent of the acres treated in 2017. Pest and disease pressure for a single commodity may differ by regions in some cases. The pooled figures in this report may not reflect differences in pesticide use patterns between production regions.

Acres treated by top 13 commodities: For these 13 commodities, the top five non-adjuvant AIs applied to the most area were sulfur, glyphosate, abamectin, oil, and copper. Sulfur was applied mostly to wine grape and table and raisin grape, although it was used on all 13 commodities except rice. Sulfur is a natural fungicide favored by both conventional and organic farmers and is used mostly to manage powdery mildew on grapes. It can also be used on some crops to suppress mites. Glyphosate is a broad-spectrum herbicide and crop desiccant. Glyphosate was used on all 13 commodities although 41 percent of the use was on almond. Although not used on every one of the 13 commodities, the following AIs were used on over one million cumulative acres: the insecticides (and miticides) abamectin, lambda-cyhalothrin, bifenthrin, methoxyfenozide, imidacloprid, chlorantraniliprole, and petroleum and mineral oils; the herbicides oxyfluorfen and glufosinate-ammonium; and the fungicides copper, azoxystrobin, and pyraclostrobin.

Pounds applied to top 13 commodities: Sulfur was the most used AI by pounds as well as by acres treated for these 13 commodities. Petroleum and mineral oils were second to sulfur in amount of pounds of non-adjuvant pesticides. Almond, orange, wine grape, and peach and nectarine had the highest use of oils out of the 13 commodities. Oils are mostly used as insecticides, but can also be used as fungicides and adjuvants. The remaining top five AIs by pounds included the fumigants 1,3-dichloropropene and chloropicrin, and the herbicide glyphosate.

Information used to develop the trend analyses for each of the thirteen crops in this chapter was drawn from several publications and from the expertise of pest control advisors, growers, University of California Cooperative Extension farm advisors and specialists, researchers, and commodity association representatives. DPR scientists analyzed the information, using their knowledge of pesticides, California agriculture, pests, and pest management practices. As a result, the explanations for changes in pesticide use are largely based on the subjective opinions of experts as opposed to rigorous statistical analyses. Additional figures of pesticide distribution maps and graphs associated with each crop can be found in the Appendix of this document (Appendix figures are referenced by an "A" preceding the figure number). Note that graphs and tables of this section are based on statewide totals which may not accurately reflect regional differences in environmental conditions, pest pressure, and pesticide use patterns of crops grown in multiple, geographically-distinct areas of California.

Alfalfa

Alfalfa is grown primarily as a forage crop, providing protein and high energy for dairy cows and other livestock. Alfalfa flowers supply the nectar that bees use to make alfalfa honey, the main honey crop in the nation. Alfalfa is also an important rotation crop that has numerous ecosystem benefits. Scientific papers have reported that alfalfa can provide ecosystem services such as improving air and water quality, soil conservation, carbon sequestration, nutrient and energy cycling, species biodiversity, and benefits to rural ecosystem functioning.

California is the leading alfalfa hay-producing state in the United States. There are six main alfalfa growing regions in California, with a wide range of climatic conditions (Figure A-3):

• Intermountain region (Northeastern region of California)
• Sacramento Valley (Central Valley north of the Sacramento - San Joaquin River Delta)
• San Joaquin Valley (Central Valley south of the Sacramento - San Joaquin River Delta)
• Coastal Region (Monterey, San Luis Obispo, and Santa Barbara area)
• High Desert (North and east of the Los Angeles Basin)
• Low Desert (Imperial and Palo Verde Valleys)

The price received per ton of hay increased by 12.9 percent in 2017 after having reached one of its lowest values in 2016 (Table 22). In addition, the number of acres harvested decreased by 8.33 percent, and was at its lowest since the 1930s. These two factors may account for some of the observed trends in pesticide use in alfalfa in 2017. (Figures 14, A-4, and A-5).

Domestic dairies are the primary U.S. market for alfalfa, but exports to China, Japan, and Saudi Arabia have increased. The decrease in acres harvested, according to an expert source, may be due to a large dairy surplus and a move to reduce pounds of alfalfa hay fed to dairy cows. Dairy farmers are reducing the amount of alfalfa fed to dairy cows to keep production costs down. Alfalfa exports are expected to continue to increase as dairymen continue to reduce the proportion of hay fed to cows due to unprofitable milk prices.

Table 22: Total reported pounds of all active ingredients (AI), acres treated, acres harvested, and prices for alfalfa each year from 2013 to 2017. Harvested acres are from USDA(a) 2014 - 2018; marketing year average prices are from USDA(c), 2016 - 2018; Acres treated means cumulative acres treated.

Figure 13, PNG: Acres of alfalfa treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Overall use of insecticides decreased in 2017 (Figure 13). The pounds of insecticides decreased by eight percent while acres treated decreased by one percent. This decrease in insecticide use may be due in large part to the reduced number of acres harvested. In 2017, insecticides made up 33 percent of the total amount of pesticides used to treat alfalfa acres. The top five insecticides were lambda-cyhalothrin, dimethoate, indoxacarb, methoxyfenozide, and chlorpyrifos (Figure 14). The organophosphate dimethoate, the oxadiazine indoxacarb, and the pyrethroid lambda-cyhalothrin were used less. Indoxacarb use decreased the most with nearly 18 percent fewer acres treated. Lambda-cyhalothrin was the insecticide with the highest acres treated at 358,957 acres, despite a 2.6 percent decrease in use. Overall, use of the entire pyrethroid chemical class decreased by 2.5 percent in 2017, making it the third consecutive year where its use on alfalfa declined. According to an expert source, the decline in pyrethroid use may be due to increasing pest resistance to pyrethroids in the Low Desert and Intermountain regions, where alfalfa is primarily grown as a permanent crop with little crop rotation practices. Growers in these regions do not rotate out the alfalfa crop for two years to reduce alfalfa weevil pest pressure. They instead rely largely on pyrethroid insecticides for control, which may contribute to the weevil's resistance to the AI.

Chlorantraniliprole and methoxyfenozide are often used to control caterpillars such as armyworms. Chlorantraniliprole, a broad-spectrum, anthranilic diamide insecticide, increased in acres treated by 89 percent, with a total of 108,752 acres treated. Of the top five insecticides, methoxyfenozide had the largest increase in use since 2016 at 28 percent, for a total of 154,035 acres treated. There were large outbreaks of armyworm infestations reported throughout the Intermountain region, which may account for the increased use of chlorantraniliprole and methoxyfenozide. The organophosphate chlorpyrifos became a restricted material in July 2015. Its use in alfalfa increased by 11.6 percent, with 153,393 acres treated, which may be attributed to pyrethroid resistance. Flupyradifurone, a relatively new AI since 2015, increased in acres treated by 65 percent, with 114,705 acres treated. An expert source indicated that as the value of alfalfa hay increases, the insecticide use to control armyworms and alfalfa caterpillar is also likely to increase.

The acres treated with herbicides decreased two percent in 2017 (Figure 13). Herbicides make up about 29 percent of alfalfa cumulative acres treated with pesticides. The top five herbicides by acres treated in 2017 included glyphosate, pendimethalin, clethodim, imazamox (ammonium salt), and paraquat dichloride (Figure 14). Of the top five herbicides, paraquat dichloride had the largest percentage decrease by acres treated in 2017, with a 34 percent decrease, a difference of 48,711 fewer acres treated. Clethodim, a broadleaf herbicide, increased by 22 percent, with a total of 242,346 acres treated. Glyphosate was applied to 270,350 acres in 2017, an increase of five percent that may be due in part to the use of genetically modified seeds resistant to glyphosate. The genetically modified alfalfa allows for use of glyphosate during establishment when young plants are more vulnerable to competition from weeds.

Area treated with fungicides increased by 14 percent. Use of fungicides in alfalfa continues to be minimal compared to the use of insecticides and herbicide, representing less than one percent of acres treated with all pesticides.

Figure 14, PNG: Acres of alfalfa treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

There were 35,450 acres treated with non-adjuvant biopesticides in 2017, an increase of 50 percent. The use of Bacillus thuringiensis increased 45 percent, with a total of 29,419 acres treated, the largest number of acres treated since 2006. An armyworm outbreak in the Intermountain region may account for the increased use of B. thuringiensis, which is used to treat first and second instar armyworm larvae. The biopesticide fungicide potassium phosphite increased in acres treated by 367 percent, with a total of 2,019 acres treated.

Almond

California produces over 80 percent of the world's almond supply. There are approximately 1.33 million almond acres, located over a 400-mile stretch from northern Tehama County to southern Kern County in the Central Valley (Figure A-6). Total acres planted increased by seven percent while total bearing acreage increased by six percent in 2017 (Table 23).

Table 23: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for almond each year from 2013 to 2017. Planted acres are from CDFA(a) 2015 - 2018; marketing year average prices are from USDA(d) 2016 - 2018; Acres treated means cumulative acres treated.

Almond acreage treated with insecticides (including miticides) increased by five percent in 2017, which can be attributed to the increase in bearing acreage (Figure 15). Abamectin, petroleum and mineral oils, methoxyfenozide, chlorantraniliprole, and bifenthrin were the top five insecticides used in 2017 by acres treated (Figure 16). Major insect pests for almond include navel orangeworm, peach twig borer, web-spinning spider mites, leaffooted bug, San Jose scale, and ants. Abamectin was the most used insecticide in 2017, with an increase of 15 percent in acres treated compared to 2016. Oils (petroleum and mineral) were the second most used insecticides, with very little change in acres treated since 2016. Abamectin is used for web-spinning mite control and its use has been steadily increasing over the years. In 2017, it was most used in May, prior to leaf hardening. Other miticides were used in the summer months (June and July), suggesting an outbreak of web-spinning spider mites later in the season. Fenazaquin, a relatively new foliar miticide, started being used on almond acreage in 2016 and its use almost doubled in 2017. Cyflumetofen, another relatively new miticide that started being used on almonds in 2015, was applied on 21 percent less acreage in 2017 compared to 2016. (Figures 15, 16, A-7, and A-8).

Figure 15, PNG: Acres of almond treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available..

The summer of 2017 had above average temperatures. The higher temperatures combined with the added acreage may have led to an increase in pest pressure from navel orangeworm. Navel orangeworm is the chief pest associated with almond production, and increased acreage can increase navel orangeworm pest pressure because they can fly a quarter-mile or more to find a new host. Not only does navel orangeworm cause direct yield losses to growers, but also market issues for the handlers since damage can lead to aflatoxin contamination, a major food safety concern. Bifenthrin, a pyrethroid used to control both navel orangeworm and leaffooted bug, was used on 16 percent more acreage in 2017. Methoxyfenozide and chlorantraniliprole are the other main insecticides used to control navel orangeworm and their use increased by 12 percent and 25 percent respectively in 2017. The use of Burkholderia spp. strain A396, a biopesticide introduced in 2015 which can be used on almonds against peach twig borer and navel orangeworm, was used on 122 percent more acreage compared to 2016. Chromobacterium subtsugae strain PRAA4-1, a biopesticide introduced in 2013 with similar uses, was used on 236 percent more acreage than in 2016.

Herbicide use increased by six percent, which is in line with the increase in acreage for 2017 (Figure 15). The top five herbicides used in 2017 include glyphosate, oxyfluorfen, glufosinate-ammonium, paraquat dichloride, and saflufenacil (Figure 16). The acres treated with glyphosate increased by five percent while paraquat dichloride and glufosinate-ammonium use increased by six and 50 percent respectively. Paraquat dichloride and glufosinate-ammonium are non-selective post-emergence herbicides that kill existing weeds on contact. Herbicide resistance to glyphosate has been increasing in recent years. Glufosinate-ammonium use has increased due to its ability to control glyphosate resistant weed species as well as increased availability of the AI for purchase on the west coast.

Acreage treated with fungicides during 2017 increased by 12 percent (Figure 15). Compared to the smaller six percent increase in bearing acreage, the increase in acres treated with fungicides suggests that there was significant disease pressure from Alternaria leaf spot, brown rot blossom blight, shot hole, and anthracnose. Rainfall, during and after bloom, is the key predictor of diseases such as brown rot blossom blight and Alternaria leaf spot. Bloom sprays are directly tied to predicted rainfall. The top five fungicides in 2017 were fluopyram, azoxystrobin, propiconazole, pyraclostrobin, and trifloxystrobin (Figure 16). Fluopyram was used on the most acreage in 2017 and its use increased by 35 percent. Azoxystrobin and propiconazole use also increased by 30 and 35 percent respectively. Fluopyram, azoxystrobin and propiconazole are fungicides used to control many diseases, such as powdery mildew and brown rot blossom blight. A recent increase in resistance has resulted in an increase in the use of other relatively new fungicides such as fluxapyroxad, which increased in acres treated by 19 percent, and penthiopyrad which increased by 46 percent. Use of potassium phosphite, a biopesticide used to control Phytophthora and Pythium, increased by 239 percent. This increase can be explained by the rainier weather and the 2016 decision by the European Union (EU) to extend its maximum residue limit (MRL) for phosphite-containing products until March 1, 2019.

Figure 16, PNG: Acres of almond treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Overall, fumigant use decreased by five percent in 2017 (Figure 15). Fumigants have multiple functions in almond production: post-harvest insect control during storage, pest control to meet phytosanitary and food safety standards, and pre-plant soil fumigation to control soil borne diseases and nematodes. The top five fumigants in 2017 were aluminum phosphide, 1,3-dichloropropene, chloropicrin, methyl bromide, and sulfuryl fluoride (Figure 16).

Carrot

California is the leading state for carrot production in the nation, producing 2.7 billion pounds of carrots (both fresh and processing) in 2017 (71 percent of total U.S. production). California has four main carrot production regions: the San Joaquin Valley (Kern County), the Central Coast (San Luis Obispo, Santa Barbara, and Monterey counties), the low desert (Imperial and Riverside counties), and the high desert (Los Angeles County) (Figure A-9). The San Joaquin Valley accounts for more than half the state's acreage.

In 2017, a total of 62,500 acres of carrots were planted in California, an increase of 2.5 percent from 2016. While the acres treated with fumigants and herbicides remained nearly the same, the acres treated with fungicides and insecticides increased (Figure 17). Nematodes, weeds, leaf blights, cavity spot, rots, and aphid remained the major pest concerns.

Figure 17, PNG: Acres of carrot treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Table 24: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for carrot each year from 2013 to 2017. Planted acres and marketing year average prices are from USDA(e) 2016 - 2018. Acres treated means cumulative acres treated.

The most-applied fungicides by acres treated in 2017 were sulfur, mefenoxam, copper, pyraclostrobin, and cyazofamid. Fungicide-treated acreage increased 24 percent while the amount used (pounds) increased 35 percent since 2016. This increase was mostly due to higher use of sulfur (around 40 percent) in both total pounds and acres treated. Sulfur is applied in conventional and organic farms mainly to manage powdery mildew (Figures 18, A-10, and A-11).

Figure 18, PNG: Acres of carrot treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

In 2017, the most-applied herbicides in carrot production by treated area were linuron, pendimethalin, fluazifop-p-butyl, clethodim and trifluralin. Use of clethodim, a grass-selective herbicide, continued to increase (26 percent) from 2016 (Figure 18).

In 2017, the most-used insecticides by treated area remained the same as the previous year: esfenvalerate, Purpureocillium lilaciunum Strain 251 (formerly Paecilomyces lilacinus), imidacloprid, methoxyfenozide, and s-cypermethrin (Figure 18). Use of methoxyfenozide, a selective insecticide that controls lepidopterous pests, noticeably increased by acres treated (153 percent) and applied pounds (240 percent) since last year.

Fumigants are used to control soil-borne diseases, nematodes, and weeds. Metam-potassium (potassium N-methyldithiocarbamate), 1,3-dichloropropene, and metam-sodium are the top three most applied fumigants in carrots. The use of metam-potassium and metam-sodium slightly increased since 2016 (Figure 18).

Cotton

Cotton is one of the top twenty commodities grown in California, with a value of over $550 million in 2017. Total planted cotton acreage increased in 2017 by 39 percent (Table 25), in part due to the heavy winter rains which helped reverse the decreasing acreage that resulted from regulatory constraints imposed on irrigation during the drought. Market demand for cotton has been increasing. Three varieties of cotton – Pima, California Upland, and San Joaquin Valley (SJV) Acala (a very high quality Upland) – make up most of the cotton acreage in California. Nearly all SJV Acala and Pima produced in the U.S. is from California. Most cotton is grown in the southern San Joaquin Valley, with smaller acreages grown in Imperial and Riverside counties and a few counties in the Sacramento Valley (Figure A-12). Over 80 percent of the San Joaquin Valley cotton is Pima. Pounds of pesticides increased by 54 percent and acres treated by 59 percent in 2017, likely due to the large increase in planted acreage (Table 25).

Table 25: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for cotton each year from 2013 to 2017. Planted acres are from USDA(a), 2014 - 2018; marketing year average prices from 2013 to 2015 are from CDFA(c), 2016; marketing year average prices after 2015 are no longer available. Acres treated means cumulative acres treated (see explanation p. 14).

Note: The CDFA and USDA no longer report the price of cotton in California in order to avoid disclosure of individual operations.

Figure 19, PNG: Acres of cotton treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Western lygus plant bug (referred to as "lygus") is the most widespread pest in cotton, with spider mites (especially strawberry spider mite), whiteflies, aphids, and thrips being important pests in some years but not others. Thrips and spider mites usually cause more problems for Upland varieties than Pima cotton. Late season aphids and whiteflies are a serious concern because they produce honeydew, a sugary excretion that drops onto the cotton lint creating a condition called sticky cotton. When ginned, sticky cotton produces a lower quality cotton lint, thus reducing the price growers receive. Caterpillars such as armyworms can cause early-spring damage to seedlings in the San Joaquin and Sacramento valleys, although they are not usually considered primary pests due to the limited injury they cause and sporadic pest pressure.

The year 2017 was noteworthy for its sustained lygus and aphid pest pressure throughout much of the San Joaquin Valley. Lygus pressure began midway through cotton squaring and continued through the late flowering stage, requiring as many as five to six pesticide applications (Figure A-14). Aphid pressure lasted all the way through open boll stages in some areas, making it one of the most difficult aphid seasons in the last twenty years. Regions outside the San Joaquin Valley did not experience such intense pest pressure. Pounds of insecticide (including miticides) increased by 63 percent and treated acreage increased by 62 percent (Figure 19). The top five insecticides by acres treated did not change since last year: flonicamid, abamectin, acetamiprid, imidacloprid, and novaluron (Figure 20). Most of these insecticides treat lygus, aphids or whiteflies, as well as an assortment of various other pests. Abamectin is used to control mites.

Pounds of herbicide increased by 34 percent, while acres treated increased by 28 percent (Figure 19). Glyphosate had the highest use in both pounds and acreage, likely due to plantings of glyphosate-resistant cotton. Oxyfluorfen, pendimethalin, and paraquat dichloride were also in the top five by both pounds and acreage. In addition, flumioxazin made the top five herbicides by acres treated, and glufosinate-ammonium edged out trifluralin in 2017, joining the top five by pounds. The increase in glufosinate-ammonium (33 percent increase in treated acres, 101 percent increase in pounds) may be due to plantings of glufosinate-ammonium - resistant cotton (Figure 20).

Herbicides applied from August through November were assumed to be used as harvest aids. The use of harvest aids increased in both pounds and acres treated. Mepiquat chloride had the largest increase in acreage by 83 percent, followed by thidiazuron, diuron, ethephon, and pyraflufen-ethyl, which all increased between 30 to 45 percent in acres treated since 2016 (Figure 20).

Figure 20, PNG: Acres of cotton treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

There is relatively low use of fungicides on cotton compared to insecticides, herbicides, and harvest aids. However, in 2017, fungicide use increased 282 percent by acres treated and more than tripled in pounds, possibly due to diseases resulting from the environmental conditions created by heavy rains. Nonetheless, pounds of fungicides made up just under one percent of all pesticides used on cotton. Azoxystrobin and iprodione were applied to the highest number of acres as well as had the largest increases in use. Potassium phosphite, pyraclostrobin, and propiconazole made up the remaining top five fungicides by acres treated (Figure 20).

Fumigant use in cotton was negligible. Although fusarium oxysporum f. sp. vasinfectum race 4 (Race 4 FOV) continues to be an ongoing concern throughout the San Joaquin Valley, use of resistant varieties is the preferred way of handling this disease rather than fumigants.

Orange

California has the highest valued citrus industry in the United States. Citrus is grown in four major areas in California. The San Joaquin Valley region comprises nearly 65 percent of the state's acreage and is characterized by hot, dry summers and cold, wet winters. The Interior region includes Riverside and San Bernardino counties and inland portions of San Diego, Orange, and Los Angeles counties and is marginally affected by the coastal climate. The Coastal-Intermediate region extends from Santa Barbara County south to the San Diego County Mexican border and has a mild climate influenced by marine air. The Desert region includes the Coachella and Imperial valleys where temperatures fluctuate wildly (Figure A-15).

Table 26: Total reported pounds of all active ingredients (AI), acres treated, acres bearing, and prices for orange each year from 2013 to 2017. Bearing acres and marketing year average prices are from USDA(b) 2015 - 2018. Acres treated means cumulative acres treated (see explanation p. 14).

Total bearing acres decreased in 2017 by 3.3 percent (Table 26), continuing a six-year decline. The declining acreage may be due in part to a reduction in available irrigation water due to the drought in 2014 and 2015, according to a Capital Press article quoting the director of industry relations for California Citrus Mutual. Production was lower, possibly due to rain during the early-season bloom period, which can negatively impact fruit set. The price per box increased 30 percent in 2017, similar to the price in 2014.

Insecticide use increased in 2017 and has increased 58 percent in the last six years (Figure 21). The top five insecticides (including miticides) were oils, thiamethoxam, spinetoram, spirotetramat, and abamectin (Figure 22). Oils are the most widely used insecticide on oranges and their use, in both pounds and acres treated , increased in 2017, continuing a trend since 2008 (Figure 22). Oil insecticides kill soft-bodied pests such as aphids, immature whiteflies, immature scales, psyllids, immature true bugs, thrips, mites, and some insect eggs. Oils are also used to manage powdery mildew and other fungi, and as an adjuvant for many insecticide treatments in citrus.

Figure 21, PNG: Acres of orange treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

The Asian citrus psyllid (ACP), which vectors a bacterium that causes Huanglongbing or citrus greening disease, was first detected in California in Los Angeles in 2008. Since that time, ACP has spread throughout Southern California, up the Central Coast, and into the San Joaquin Valley. Attempts are being made in the San Joaquin Valley to eradicate ACP using a combination of foliar pyrethroids to kill all life cycle stages, and the neonicotinoid imidacloprid which is distributed systemically throughout the tree and causes death when consumed by the insect. Some pesticides show better efficacy against one life cycle stage or another. Area-wide treatments using abamectin, beta-cyfluthrin, cyfluthrin, thiamethoxam, and spirotetramat, as well as many other insecticides, are being conducted in Southern California where the insect is established. Use of many of these chemicals has increased since 2013. Despite eradication efforts, treatments have not prevented the spread of ACP and it remains a major concern.

Chlorpyrifos is a broad-spectrum insecticide used primarily for citricola scale management. It recently became a restricted material in 2015. Chlorpyrifos resistance in citricola scale has been documented and imidacloprid is increasingly being used to suppress these resistant populations. Imidacloprid is also used in the required treatment of glassy-winged sharpshooter. Both chlorpyrifos and imidacloprid use decreased in pounds and acres in 2017 (Figure A-17).

South Korea is a major California navel orange export market and Fuller's rose beetle is a quarantine pest that has required pesticide treatments since 2013. The weevil does not cause economic damage in California, but it is hard to kill. California growers are required to apply two insecticide treatments on exports to South Korea. Thiamethoxam is the most common choice. Thiamethoxam was first used in 2010 and its use has rapidly increased since that time. It is the second most used insecticide by acres, and increased by 112 percent in pounds applied since 2013 (Figure 22).

Figure 22, PNG: Acres of orange treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Spinosad and spinetoram are primarily used in citrus to manage citrus thrips (Figure 22). Both are selective active ingredients, meaning they are somewhat less toxic to non-targeted organisms such as natural enemies. According to one expert, they may eventually take over the market share of older insecticides.

California red scale populations were high in 2015 and 2016 due to the relatively warm, dry winters and hot summers. Winter weather in 2017 was wet and cold with early rains, and populations of scale declined. Spirotetramat is used on the younger instar of California red scale and it is also effective for citrus red mite, citrus leafminer, and citrus thrips. Pyriproxyfen is a selective insect growth regulator and is used almost exclusively for California red scale.

Fenpropathrin is used to manage red mites, citrus thrips, Asian citrus psyllid, katydids, and other miscellaneous pests. The insecticidal activity of fenpropathrin is similar to that of beta-cyfluthrin.

Abamectin is used for thrips, mites, and citrus leafminer. It is preferred because it is inexpensive and has broad-spectrum and long residual activity, low worker risk, and a short pre-harvest interval. Dimethoate is used for a variety of pests such as scales and thrips. Its declining use is likely due to the growing popularity of replacement insecticides such as spinetoram and the neonicotinoids imidacloprid and acetamiprid. In the San Joaquin Valley, populations of armored scale show resistance to chlorpyrifos, methidathion, and carbaryl, and growers are encouraged to release parasitic wasps and use buprofezin, oil, pyriproxyfen, and spirotetramat.

Two new insecticides, flupyradifurone and cyantraniliprole, have generally increased since they were first used in 2015. Flupyradifurone use increased in acres and pounds in 2017, doubling the acres used in 2016 for a total of 3,447 acres in 2017. Although cyantraniliprole decreased after its first year in 2015, it slightly increased in acreage in 2017 to 12,604 acres.

Fungicides are used to prevent Phytophthora gummosis, Phytophthora root rot, and fruit diseases such as brown rot and Septoria spot. These diseases are exacerbated by wet, cool weather during harvest, as was the case in 2017. As a result, fungicide use increased in both pounds and acres treated by about 13 percent in 2017, largely due to a substantial increase in the top five frequently used fungicides: copper, mefenoxam, pyraclostrobin, potassium phosphite, and azoxystrobin (Figures 21, 22, and A-16).

Weed management is important in citrus groves to prevent competition for nutrients and water, which affects tree growth and reduces yield. Excessive weed growth also impedes production and harvesting operations. Both pre-emergence and post-emergence herbicides, as well as mechanical removal, are used to control weeds. Herbicide use decreased substantially in 2017, with a 16 percent decrease in acres treated and a 20 percent decrease in pounds applied (Figure 21). Glyphosate, a post-emergence herbicide, was the most-used herbicide by acres treated, followed by indaziflam, rimsulfuron, saflufenacil, and glufosinate-ammonium (Figure 22). Simazine is widely used for pre- and post-emergence weed management. Saflufenacil, a post-emergence, burn-down herbicide first used in 2010, is replacing glyphosate for use on horseweed and fleabane due to resistance. Indaziflam, a pre-emergence herbicide was used on fewer acres in 2017, but its use had been increasing each prior year since its registration in 2011. Rimsulfuron use continued declining following the end of a generally upward trend in 2015, with a 19 percent decrease in 2017 (Figures 21, 22, and A-16).

Plant growth regulators decreased by seven percent. 2,4-D and gibberellins were the only two growth regulators used in 2017, both decreasing in acres treated by six to eight percent (Figure 22).

The use of biopesticides such as kaolin and potassium phosphite increased in 2017. Kaolin, a white nonabrasive fine-grained mineral that is sprayed on the plants to form a particle film, is used as a fungicide and insecticide. A recent study in Brazil investigated the influence of two kaolin formulations on the landing and feeding behavior of ACP. Both kaolin formulations had a repellent effect and interfered with the feeding behavior of ACP on citrus. Kaolin reduced the number of psyllids and protected the citrus plants from insect feeding. Kaolin use increased 12 percent by pounds in 2017. Potassium phosphite is a biopesticide that is used as a fungicide, effective for Alternaria brown spot. Its use increased 61 percent by pounds applied and 75 percent by treated acres in 2017.

Peach and nectarine

California grew 78 percent of all U.S. peaches (including 56 percent of fresh market peaches and 96 percent of processed peaches) and 94 percent of nectarines in 2017. Most freestone peaches and nectarines are grown in Fresno, Tulare, and Kings Counties in the central San Joaquin Valley and sold on the fresh market. Clingstone peach, largely grown in the Sacramento Valley, is exclusively canned and processed into products such as baby food, fruit salad, and juice (Figure A-18). Peach and nectarine are discussed together because pest management issues for the two crops are similar.

Table 27: Total reported pounds of all active ingredients (AI), acres treated, acres bearing, and prices for peach and nectarine each year from 2013 to 2017. Bearing acres and marketing year average prices are from 2013 to 2014 are from USDA(d)2016 - 2018. Acres treated means cumulative acres treated.

The price per pound in Table 27 is an average of the prices of peach and nectarine, weighted by their respective acreages. Due to the wide variation in individual prices, it is best to consult USDA and CDFA for specific prices.

Cumulative peach and nectarine acreage treated with insecticides (including miticides) increased five percent in 2017 despite a decrease of five percent in bearing acreage (Figure 23). The top five insecticides by acres treated include oils, abamectin, chlorantraniliprole, esfenvalerate, and spinetoram (Figure 24). The data suggests that mites, peach twig borer, leafrollers, ants, and moth larvae were all major pests in 2017. Oil was used on the most acreage in 2017, although its use decreased by one percent. Oils are applied during the dormant season or during the growing season to prevent outbreaks of scales, mites, and moth species (Figure A-20). Abamectin, a miticide, ranked second to oil for the most treated acreage, increasing by 12 percent. The acres treated with chlorantraniliprole, an insecticide that controls many moth species, increased by five percent. Acres treated with spinetoram remained relatively constant (0.50 percent increase). Spinetoram is applied to control moths, katydids, and thrips.

Figure 23, PNG: Acres of peach and nectarine treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Figure 24, PNG: Acres of peach and nectarine treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Acres treated with herbicides decreased 9 percent (Figure 23). The acres treated with glyphosate, oxyfluorfen, rimsulfuron, and pendimethalin all decreased in 2017 (Figures 24 and A-19). Pre-emergence herbicides such as oxyfluorfen, pendimethalin, rimsulfuron, and indaziflam are applied to soil before the growing season to prevent weed sprouting. Post-emergence herbicides such as glyphosate, 2,4-D, pyraflufen-ethyl, and paraquat kill existing weeds on contact.

Glufosinate-ammonium was not used much in past years due to its limited supply on the west coast, but its use has been continually increasing over the last few years, with a six percent increase in acres treated in 2017. Glufosinate-ammonium is a broad spectrum herbicide that has gained popularity in recent years because of its ability to control glyphosate-resistant weed species.

Cumulative acreage of peach and nectarine orchards treated with fungicides during 2017 increased by 14 percent, while acres treated with sulfur decreased by eight percent (Figure 23). Brown rot, powdery mildew, scab, and rust are the top diseases for peach and nectarine. Acres treated with propiconazole, ziram, copper, and fluxapyroxad all increased in 2017, while pyraclostrobin decreased by five percent (Figure 24). Sulfur is customarily used to prevent powdery mildew but it does not treat the infection once established. Metconazole, a fungicide used to control powdery mildew and brown rot, continued to increase in acres treated. Resistance of other demethylation inhibitors or (DMI) fungicides, such as propiconazole, has been a contributing factor to the increase in metconazole use. Brown rot is the chief cause of postharvest fruit decay, but gray mold (known as Botrytis bunch rot when it infects grapes), Rhizopus rot (aka black bread mold), and sour rot can also pose significant problems.

Fumigant use is relatively small compared to other types of pesticides used on peaches and nectarines, representing 0.1 percent of the acres treated with all pesticides. Acreage treated with fumigants increased by two percent in 2017. Fumigants are used in peach and nectarine orchards for rodent control and for pre-plant soil treatments against arthropod pests, nematodes, pathogens, and weeds. Acres treated with aluminum phosphide, a rodent control, increased by 40 percent for a total of 216 cumulative acres treated. Aluminum phosphide requires, and works best in, moist soils. Area treated with the most widely-used pre-plant soil fumigant 1,3-D, increased by 16 percent while chloropicrin decreased by 46 percent. Changing relationships between nematode infestations, pathogen infections, rootstock choices, and application patterns affect fumigant selection and use from year to year.

A cumulative total of 1,192 acres of peaches and nectarines were treated with plant growth regulators in 2017. Gibberellins, plant hormones that regulate growth and development, were applied to 865 acres, a six percent decrease from 2016. Acres treated with amino ethoxy vinyl glycine hydrochloride, an ethylene synthesis inhibitor applied during bloom, decreased by 34 percent. Both chemicals can enhance the firmness, size, and durability of fruit.

Pistachio

In 2017, California accounted for 250,000 bearing acres of pistachio, or about 99 percent of the U.S. crop (Table 28). Utilized production in California was 600 million pounds, down 33 percent from 2016. Bearing acreage increased five percent from 2016 to 2017.

Table 28: Total reported pounds of all active ingredients (AI), acres treated, acres bearing, and prices for pistachio each year from 2013 to 2017. Bearing acres and marketing year average prices are from USDA(d) 2016 - 2018. Acres treated means cumulative acres treated (see explanation p. 14).

Pistachio is grown in 22 counties, from San Bernardino County in the south, to Tehama County in the north. Ninety-seven percent of the bearing acreage is in the San Joaquin Valley counties of Kern, Madera, Merced, Kings, Fresno, and Tulare (Figure A-21). Pistachio bearing acreage is expected to increase during the next few years due to a surge in planting that began in 2011. Pistachio production in 2017 was slightly below average.

Wet soil during the winter mummy-nut sanitation period reduced access to orchards and led to significantly increased navel orangeworm populations during the summer and at harvest time in September. The spring was unusually cool which slightly delayed spring insect pest development. The summer was unusually hot with degree-days for Fresno from the first week of May through the first week of September running at 25 percent above normal. A degree day is a unit that can be used to measure developmental rate for organisms whose physiological development is controlled by heat.

Acres treated with pesticides increased six percent from 2016 to 2017 due to increased bearing acres and additional treatments for perceived threats from pests. The percentage of non-bearing to total acreage has remained constant at about 24 percent from 2013 through 2017. However, the ratio of acres treated to acres bearing has increased from 17:1 in 2013 and 2014, to 19:1 in 2015, to 21:1 in 2016 and 2017.

In 2017, important arthropod pests of pistachio included mites, leaffooted plant bugs, false chinch bug, stink bugs, and navel orangeworm. Feeding by leaffooted plant bugs (a complex of three Leptoglossus species) shortly after the April bloom can cause lesions on the expanding nuts, which leads to kernel necrosis after the shell hardens in June. Growers often preemptively apply insecticides such as lambda-cyhalothrin and bifenthrin before the bugs cause damage. Spring use of both of these insecticides began in April and peaked in May (Figures 25, A-22, and A-23).

Figure 25, PNG: Acres of pistachio treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Navel orangeworm damages nuts in August (third generation) and September (fourth generation). Insecticide applications target the larvae of these two generations as they hatch beginning in late July and ending in mid-September (Figure A-23). In 2017, because the summer was warmer than normal, the third generation coincided with nut maturation and, because the navel orangeworm population was large, growers responded by applying additional sprays of pesticides. Also, because navel orangeworm generations were synchronized with nut maturation, early harvest before the fourth generation was not an option so pesticide application continued late into the season. Those applications are reflected in the increased use of lambda-cyhalothrin, chlorantraniliprole, methoxyfenozide, and spinetoram in August.

Total insecticide use has increased dramatically since 2010 and the ratio of acres treated with insecticides to acres bearing has increased from 2:1 to 6:1 in only seven years (Figure 25). Acres treated with insecticides (including miticides) increased by six percent since 2016 (Figure 25). The top five insecticides by acres treated included lambda-cyhalothrin, bifenthrin, chlorantraniliprole, methoxyfenozide, and imidacloprid (Figure 26).

Herbicide use has increased almost at the same rate as insecticide use since 2014. In 2017, the acres treated with herbicides increased by 14 percent (Figure 25). The top five herbicides by acres treated included glyphosate, glufosinate-ammonium, oxyfluorfen, saflufenacil, and paraquat dichloride (Figure 26). The steady increase in the contribution of glufosinate-ammonium to the total since 2014 likely reflects its use to control weeds that have developed resistance to glyphosate. Also, the lack of availability of glufosinate-ammonium in the west coast in 2014 and 2015 resulted in low use that did not really reflect its high demand at the time. The peak use of glyphosate, glufosinate-ammonium, saflufenacil, and paraquat dichloride is during the summer irrigation season. Oxyfluorfen is primarily used during the wet season from October through March.

The acres treated with fungicides dropped by about 15 percent (Figure 25). The top five fungicides by acres treated included Aspergillus flavus, strain AF36, metconazole, pyrimethanil, fluopyram, and pyraclostrobin (Figure 26). Fluopyran and pyraclostrobin use decreased (Figure 26) likely due to the evolution of resistance to them by Alternaria alternate (late-blight). Use of Aspergillus flavus, strain AF36, continued to increase. It is a fungal inoculant that acts as a biological control agent and prevents contamination of nuts by aflatoxins. The aflatoxin-producing fungi, a complex of Aspergillus flavus and A. parasiticus, grow on pest-damaged nuts. Aflatoxins are both toxic and carcinogenic. About half of the strains of A. flavus found in the orchard are atoxigenic – that is, they do not produce aflatoxin. However, almost all A. parasiticus strains produce aflatoxins. When applied to orchards, the atoxigenic strain of A. flavus, AF36, prevents aflatoxin-producing strains from establishing and significantly reduces aflatoxin levels in harvested nuts.

Sulfur, used as a low-risk miticide, is applied at several pounds per acre once per season, and is used to manage citrus flat mite. The acres treated with sulfur increased by 13 percent (Figure 25). The mites feed on the stems of nut clusters as well as the nut hulls and nuts themselves, which can lead to shell stain. As the weather warms up in May, mite populations thrive and peak in late July and August. Sulfur is applied May through August to control those populations (Figure A-23).

Figure 26, PNG: Acres of pistachio treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Processing tomato

In 2017, processing tomato growers planted 230,000 acres, yielding 10.5 million tons, a 17 percent yield decrease from 2016. About 95 percent of U.S. processing tomatoes are grown in California. The U.S. is the world's top producer of processing tomatoes, contributing 34 percent of total production, followed by the European Union and China. California processing tomatoes, valued at $848 million in 2017, are primarily grown in the Sacramento and San Joaquin Valleys (Figure A-24). Fresno County leads the state in acreage with 31 percent (72,000 acres) of the statewide total, followed by Yolo County (33,000 acres), Kings County (25,000 acres), and San Joaquin County (20,000 acres). Significant production also occurs in Merced, Colusa, Kern, Stanislaus, and Solano counties.

Table 29: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for processing tomato each year from 2013 to 2017. Planted acres for 2016 and 2017 are from USDA(f), 2018; planted acres from 2013 to 2015 are from USDA(e); marketing year average prices are from USDA(e) 2016 - 2018. Acres treated means cumulative acres treated (see explanation p. 14).

Total cumulative treated acres of processing tomatoes decreased 21 percent in 2017 (Table 29). Sulfur, chlorothalonil, metam-sodium, glyphosate, and potassium N-methyldithiocarbamate (metam-potassium) accounted for 90 percent of the total pounds of pesticide AIs applied, while sulfur, s-metolachlor, chlorothalonil, trifluralin, and imidacloprid were applied to the most acreage. The most-used pesticide type as measured by acres treated was insecticides, which decreased 17 percent (Figure 27). The most-used category as measured by the pounds of AI applied was fungicide/insecticide (mostly sulfur and kaolin), which decreased 25 percent.

Overall fungicide use, expressed as cumulative acres treated, decreased 31 percent, while pounds of fungicide AI decreased 28 percent (Figure 27). The top five fungicides by acres treated included chlorothalonil, azoxystrobin, difenoconazole, copper, and pyraclostrobin (Figure 28). Difenoconazole and azoxystrobin use was steady, with less than one percent change in acres treated for both. 2017 was a light year for diseases in processing tomato: Acres treated with copper decreased 57 percent, while mancozeb use decreased 74 percent; mancozeb increases the efficacy of copper when they are applied together for bacterial disease control. Lower-risk fungicide use increased in 2017: pounds of the biopesticide, Bacillus amyloliquefaciens strain D747, increased over 48 percent (going from 9,263 pounds in 2016 to 14,302 pounds in 2017).

Figure 27, PNG: Acres of processing tomato treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

The acres treated with herbicides decreased 11 percent (Figure 27); the pounds used decreased 15 percent. The top five herbicides used included trifluralin, s-metolachlor, glyphosate, rimsulfuron, and oxyfluorfen (Figure 28). Primary weeds of concern for processing tomatoes are nightshades and bindweed. Trifluralin and pendimethalin are used to control bindweed and are often used in combination with s-metolachlor. The acres treated with pendimethalin decreased three percent, while trifluralin use decreased 15 percent (Figures 28 and A-25). S-metolachlor use decreased by three percent. Glyphosate is commonly used for preplant treatments in late winter and early spring; its use decreased 25 percent. (Figures 28 and A-26).

Processing tomatoes have relatively low acres treated with fumigants compared to other types of pesticides. The acres treated with fumigants is 0.5 percent of the acres treated with all pesticides. Processing tomato growers primarily use three fumigants – metam-potassium (potassium n-methyldithiocarbamate), metam-sodium, and 1,3-dichloropropene – to manage root-knot nematodes and weeds, particularly weeds of the nightshade family. In 2017, the pounds of fumigants used decreased by 46 percent and accounted for about 16 percent of the total pounds of pesticide AIs applied. In terms of acres treated, fumigant use decreased 44 percent.

In 2017, 935,400 cumulative acres were treated with insecticides, a 17 percent decrease from 2016 (Figure 27). The top five insecticides by acres treated included imidacloprid, chlorantraniliprole, bifenthrin, lambda-cyhalothrin, and dimethoate (Figure 28). The most-used insecticide by pounds was diazinon, which showed a 120 percent increase in use from 2016. Diazinon is used both in pre-plant (to control crickets and cutworms) and post-emergence (for aphid and leafminer control) situations. Imidacloprid, which is used to control whiteflies, decreased 18 percent in acres treated from the previous year. Dimethoate, which decreased 10 percent in treated acres, is a broad spectrum insecticide used for thrips control. However, its use early in the season can disrupt natural predation and cause population explosions of other insect pests, such as leafminers, later in the season (Figure A-26). Methomyl use decreased 20 percent, as growers continue to switch to pyrethroids because of worker safety concerns. Bifenthrin, which decreased in acres treated by 17 percent, is a broad spectrum pyrethroid often used in rotation with spinosad for thrips control. Bifenthrin is also used to manage mites and stinkbugs.

Figure 28, PNG: Acres of processing tomato treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Rice

California is the largest producer of short- and medium-grain rice in the United States and the second largest rice-growing state in the nation. Ninety-five percent of the rice in California is grown in six counties in the Sacramento Valley (Colusa, Sutter, Glenn, Butte, Yuba, and Yolo, Figure A-27). The acres planted with rice decreased 17 percent, the smallest decline since 2014 and 2015 when rice farmers faced water restrictions due to four years of drought (Table 30). The yield of 8,410 pounds per acre was down five percent from a year earlier, making it the smallest yield since 2012 and 2013.

Growers experienced record winter rains. Snowfall in the mountains was followed by massive snowmelt and spring flooding. Rice planting was delayed in the spring and was followed by abnormally high temperatures. A lot of lodging, where stems are no longer upright near ground level of the crop, was observed in 2017. Lodging, which causes stems to be dry and brittle, makes harvest difficult, and limits grain yield and quality.

Table 30: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for rice each year from 2013 to 2017. Planted acres are from USDA(a) 2014 - 2018; marketing year average prices are from USDA(c) 2016 - 2018. Acres treated means cumulative acres treated.

Because much of California's rice is grown repeatedly in the same fields and there is a limited number of new herbicide modes of action, herbicide resistance is one of the major production challenges growers currently face. Grasses, sedges and broadleaf weeds make up the spectrum that challenges California rice production. The most challenging weeds are watergrass, sprangletop, bulrush and smallflower umbrella sedge. Watergrass and particularly sprangletop are showing some level of resistance to certain herbicides. Many weed species are difficult to manage and if allowed to grow unimpeded, will severely compete with the rice crop for resources.

An integrated pest management approach that incorporates various practices such as planting clean certified seed and leveling the ground is important for rice production. Land leveling allows water for weed suppression to be put on quickly, removed for pinpoint herbicide treatments, and returned efficiently back to the fields. Fields are also monitored and scouted regularly for weeds.

Herbicides were the most-used type of pesticides on rice in terms of acres treated and pounds applied. Herbicide use decreased in 2017 by 25 percent, which may be largely due to the reduced number of acres planted (Figure 29). Collaborative water monitoring efforts between the California Rice Commission and pesticide registrants have been ongoing since 2006. The top five herbicides by acres treated included propanil, triclopyr (triethylamine salt), thiobencarb, penoxsulam, and clomazone (Figure 30). The top five herbicides by pounds and treated acres all had reductions in use: Propanil, a post-emergence herbicide, was the most-used rice herbicide in California. The pounds applied decreased 28 percent in 2017, which was similar to usage in 2015 (Figures 30 and A-28). Use of thiobencarb decreased in pounds used and acres applied in 2017, but was higher than any previous year prior with the exception of 2016. This high use was probably due to the progressive resistance of sprangletop to clomazone and cyhalofop-butyl. The continuing decrease of bensulfuron methyl may have resulted from a 2013 introduction of a product that combined thiobencarb and imazosulfuron for bensulfuron methyl-resistant sedges.

Weedy rice (red rice), a close relative of cultivated rice that competes for resources, was reported on more acres in 2017 than in the previous two decades. The origin and spread of weedy rice is not well understood. Guidelines for treatment will be refined as more knowledge is gained. For larger infestations, glyphosate is used as a burndown herbicide. A new granular into-the-water herbicide product that combines two AIs with different modes of action (an HPPD-inhibitor (benzobicyclon), and an ALS-inhibitor (halosulfuron-methyl)) was registered for California use in 2017, and was used on a limited number of acres. It is the first HPPD-inhibitor available to California rice growers. This herbicide will be a new option for resistance management, particularly with herbicide resistant sedges. The number of acres treated with halosulfuron-methyl increased 144 percent.

The acres treated with fungicides decreased 14 percent (Figure 29) and the pounds applied decreased 30 percent in 2017. The acres treated were the lowest since 2010. The top five fungicides by acres treated included azoxystrobin, reynoutria, sodium percarbonate, propiconazole, and trifloxystrobin. Sodium carbonate peroxyhydrate, a fungicide (technically an algaecide/fungicide) allowed for use in organic rice production, was the most-used fungicide on rice in terms of pounds applied. Its use decreased 34 percent, the lowest since 2010. Azoxystrobin was used on the greatest number of acres, accounting for 89 percent of the acres where fungicide was applied and 26 percent of the pounds. Azoxystrobin, propiconazole, and trifloxystrobin are fungicides often used as preventive treatments.

Copper sulfate is the key algaecide registered for rice in California. It is used primarily for algal management in rice fields as well as to manage tadpole shrimp in both conventional and organic production. Copper sulfate can bind to organic matter such as straw residue and potentially reduce the algaecide efficacy. Sodium carbonate peroxyhydrate was registered as an alternative to copper sulfate to manage algae. However, it has yet to displace copper sulfate as the most used algaecide (Figure A-28).

Usually, there is little insect pressure on California rice, and insecticides are used on relatively few acres (Figure 29). However, the spring storms coupled with higher temperatures that immediately followed created the perfect environment for insects to emerge, and use of insecticides increased in 2017 by 19 and 20 percent in acres treated and pounds, respectively. With the exception of 2015, the acres where insecticides were used has been increasing for the past 10 years. The top five insecticides by acres treated included lambda-cyhalothrin, methoxyfenozide, s-cypermethrin, diflubenzuron, and Bacillus thuringiensis (Figure 29).

Figure 29, PNG: Acres of rice treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Armyworm pressure was high for a third consecutive year. The worms (caterpillars) were spotted in mid-June and caused significant defoliation in Glenn, Colusa, Butte, and Yolo counties. In most areas, the defoliation was severe, but the area affected within fields was still small. In 2015, no registered insecticide was effective in managing the significant outbreak. Multiple applications of different pesticides, predominantly pyrethroids and carbaryl or Bacillus thuringiensis, had little effect on the pest. An emergency exemption for a methoxyfenozide-containing product was first issued in 2015 and again in 2016 and 2017.

Rice water weevil is the major insect pest on California rice. Pyrethroids have been used intensively over the last 15 years for rice water weevil but the effectiveness of this insecticide is lessening (Figures 30 and A-29). Tadpole shrimp are also slowly becoming a major pest, and in some areas, they are the main pest of rice during the seedling stage. Tadpole shrimp are omnivorous crustaceans that cause damage either by chewing on parts of the seedlings or by digging in the soil to lay eggs which creates cloudy water that prevents adequate light penetration. Growers often rely on lambda-cyhalothrin, copper sulfate pentahydrate, or carbaryl, applied soon after flooding to manage tadpole shrimp.

Figure 30, PNG: Acres of rice treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Strawberry

In 2017 California produced 2.92 billion pounds of strawberries valued at more than $3.1 billion. Market prices determine how much of the crop goes to fresh market and how much is processed, however the bulk of each year's crop goes to fresh market. About 39,000 acres of strawberry were planted in 2017, primarily along the central and southern coast, with smaller but significant production occurring in the Central Valley (Figure A-30 and Table 31).

The acres treated with insecticides (including miticides) increased by two percent in 2017 (Figure 31). The top five insecticides included Bacillus thuringiensis, novaluron, flonicamid, bifenthrin, and spinetoram (Figure 32). The major insect pests of strawberry are lygus bugs and worms (various moth and beetle larvae), especially in the Central and South Coast growing areas. Until recently, lygus bugs were not considered a problem in the South Coast, but lygus has become a serious threat probably due to warmer, drier winters and increased diversity in the regional crop complex that includes more crops which support this pest. Flonicamid and acetamiprid are insecticides used to control lygus. Flonicamid was applied to 1 percent fewer acres in 2017, while acres treated with acetamiprid increased by 3 percent. Overall insecticide pounds increased by 9 percent from 2016, with 3 to 4 percent increases in neonicotinoid, organophosphate, and pyrethroid insecticides. Carbamate use decreased by 30 percent. (Figures 32, A-31, and A-32).

Table 31: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for strawberry each year from 2013 to 2017. Planted acres from 2013 to 2017 are from USDA(d) 2016 - 2018; marketing year average prices are from USDA(d) 2018. Acres treated means cumulative acres treated.

Figure 31, PNG: Acres of strawberry treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Herbicide use in 2017 decreased 31 percent by pounds and 17 percent by acres treated (Figure 31). The primary contributors to this decrease were a 21 percent decrease in oxyfluorfen use, a 20 percent decrease in pendimethalin, and an 18 percent decrease in flumioxazin. Carfentrazone-ethyl and sulfentrazone joined pendimethalin, oxyfluorfen, and flumioxazin in the top five herbicide AIs by acres treated, increasing in acres treated by 29 and 14 percent, respectively (Figure 32).

Fungicides continued to be the most-used pesticides in 2017, as measured by acres treated. Overall, acres treated with fungicides decreased by 4 percent in 2017, with most fungicides showing a slight decrease in use. (Figure 31). The top five fungicides by acres treated included captan, sulfur, captan (other related), cyprodinil, and fludioxonil (Figure 32).

Figure 32, PNG: Acres of strawberry treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Most strawberry fields are treated with fumigants. In 2017, there were 34,088 fumigant-treated strawberry acres, slightly less than the 39,000 acres planted that year. Acres treated with fumigants decreased by two percent in 2017 (Figure 31). The top five fumigant AIs by acres treated included chloropicrin, 1,3-dichloropropene, metam potassium (potassium n-methyldithiocarbamate), metam-sodium, and methyl bromide (Figure 32). Acres treated with methyl bromide and chloropicrin decreased by 99 percent and 5 percent, respectively, while metam-sodium and 1,3-dichloropropene increased by 27 percent and 11 percent, respectively. Metam-sodium is generally more effective in controlling weeds than the other fumigants, but is less effective than 1,3-dichloropropene or 1,3-dichloropropene plus chloropicrin against soilborne diseases and nematodes.

Fumigants represented less than two percent of the total cumulative acres treated with all pesticide types on strawberry, although they accounted for about 81 percent of all pesticide pounds. Fumigants usually are applied at higher rates than other pesticide types, such as fungicides and insecticides, in part because they treat a volume of space rather than a surface such as leaves and stems of plants. Thus, the amounts applied are large relative to other pesticide types even though the number of applications or number of acres treated may be relatively small.

Table and raisin grape

The southern San Joaquin Valley region accounts for more than 90 percent of California's raisin and table grape production (Figure A-33). Total acreage planted in table and raisin grapes decreased by an estimated 14,000 acres in 2017, continuing a trend that reflects a decrease primarily in raisin production. Average prices increased in 2017, after a substantial decrease in 2016 (Table 32). The California Grape Acreage survey for 2017 found that Thompson Seedless was again the leading raisin grape variety, while Flame Seedless was again the leading table grape variety. Acreage planted to both these varieties has been decreasing since at least 2008.

Table 32: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for table and raisin grape each year from 2013 to 2017. Planted acres are from CDFA(b) 2016 - 2018; marketing year average prices are from USDA(d) 2016 - 2018. Acres treated means cumulative acres treated.

The price per ton in Table 32 is an average of the prices of table and raisin grapes, weighted by their respective acreages. Due to the wide variation in prices depending on type and use of the grape, it is best to consult USDA and CDFA for specific prices. Figure

Figure 33, PNG: Acres of table and raisin grape treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

Patterns in pesticide use on table and raisin grapes are influenced by a number of factors, including weather, topography, pest pressure, evolution of resistance, competition from newer pesticide products, commodity prices, application restrictions, and efforts by growers to reduce costs. It is often difficult to isolate which factors explain particular patterns of use.

Acres treated with insecticides increased, while acres treated with sulfur and herbicides decreased in 2017. Although there was a six percent decrease in 2017, the overall trend of acres treated with sulfur has remained relatively stable since 2011. In contrast, herbicide use has trended downward for six years, and decreased by 16 percent in 2017. Insecticide use climbed between 2010 and 2013, but has remained relatively stable since then, with a five percent increase in 2017. Acres treated with fungicides changed little, a pattern that has prevailed for the past four years. (Figure 33).

The major arthropod pests in table and raisin grapes continue to be the vine mealybug, leafhoppers, western grape leaf skeletonizer and other Lepidoptera, and spider mites. Vine mealybug has now been found throughout most of the grape growing regions of California. The warm winters since 2012 have allowed vine mealybug populations to build up early in the season.

Of the top five insecticide AIs, there were small increases in acres treated with spirotetramat, spinetoram and buprofezin, and small decreases in acres treated with imidacloprid and abamectin (Figure 34). Acreage treated with abamectin has been decreasing since 2015. Another widely used insecticide, methoxyfenozide, has been used on less acreage each year since 2014. With the exception of methoxyfenozide (used for control of Lepidoptera), acres treated with the top five AIs had generally been increasing over the last decade until 2014, when use of imidacloprid, spirotetramat, and abamectin either leveled off or began to decrease. Spinetoram use has generally continued a trend of increasing use over the last decade. Bacillus thuringiensis and spinosad had large percentage increases in 2017 for control of Lepidoptera. These lower risk AIs are acceptable on organically-certified grapes. Beta-cyfluthrin, a pyrethroid was used on 30 percent more acreage in 2017. The newly registered miticide, cyflumetofen, was used on a substantially greater area in 2017 compared to 2016 (18 percent increase), but another miticide, fenpyroximate, was used on 34 percent less acreage. Growers rotate miticides to manage for resistance of highly adaptable spider mites. Use of mating disruption has been on the rise over the last few years; lavanduyl senecioate, a mealybug pheromone, was used on 416 percent more acreage in 2017 than 2016. The increase was largely due to registration in mid-2016 of a new spray formulation, which is less expensive than the dispenser-based products. Chlorpyrifos use has declined since 2014 but large vine mealybug populations have kept this AI as an important tool for growers. Chlorpyrifos is used as post-harvest or delayed dormant treatments to prevent spring buildup of vine mealybug populations.

The acres treated with fungicides remained the same as in 2016 at around 1.6 million cumulative acres (Figure 33). The top five fungicides with the greatest acres treated (copper, tebuconazole, quinoxyfen, myclobutanil, and pyraclostrobin) were mostly the same as in 2016, with the addition of pyraclostrobin (most commonly used in combination with boscalid) in place of trifloxystrobin (Figure 34and A-34). The acres treated with quinoxyfen trended upward from 2008 to 2015, but decreased slightly in 2016 and in 2017. Myclobutanil use has been decreasing since 2013. Notable increases in acres treated were observed for cyflufenamid and fenhexamid. Flutriafol use has increased from less than 1,000 acres in 2015 to nearly 14 thousand acres in 2016 and nearly 30,000 acres in 2017. Fluopyram was applied to 48,000 more acres than in 2016. Cyflufenamid use increased as well. Flutriafol was registered in 2014 and fluopyram and cyflufenamid were registered in 2012 so increases in their use might be expected as growers test new AIs and use them in rotation with other AIs. Substantial decreases in acres treated were observed for trifloxystrobin, cyprodinil and kresoxim-methyl. Much of the pattern of fungicide use across years can be explained by rotation of AIs as part of a resistance management program. Most applications were in spring to early summer, likely for powdery mildew. There were some late season applications of copper, cyprodinil, fludioxonil and fenhexamid.

Though the winter of 2016-2017 was wet, weed pressure was still relatively light and the acres treated with herbicides decreased by 16 percent, a trend that has continued since 2011 (Figure 33). The top five herbicides by acres treated included glyphosate, glufosinate-ammonium, oxyfluorfen, paraquat dichloride, and pendimethalin. All of the top five herbicides decreased in acres treated, except for glufosinate-ammonium. Glyphosate use decreased by 22 percent (Figure 34). There were reductions in acres treated with most other herbicides, except oryzalin and capric acid, which were applied to a relatively small number of acres (around 7,000 to 8,700 acres). Capric acid is an AI of an organic product approved by the Organic Materials Review Institute (OMRI) and was registered for use in grapes in 2015. The acres treated with flazasulfuron decreased by 33 percent in 2017, ending an increasing trend since it was registered in 2012.

Figure 34, PNG: Acres of table and raisin grape treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

Fumigants represented only 0.07 percent of the acres treated with all pesticides in 2017, although they made up 5.7 percent of all pesticide pounds applied to table and raisin grapes. Fumigant use increased in both pounds and acres treated, by 13 and 47 percent, respectively (Figure 33). The top five fumigants by acres treated included 1,3-dichloropropene, metam-potassium (potassium n-methyldithiocarbamate), aluminum phosphide, chloropicrin, and metam sodium (Figure 34). Most of the increase was due to applications of metam-potassium.

The acres treated with plant growth regulators decreased by four percent in 2017. Gibberellins were used the most. Ethephon, forchlorfenuron and hydrogen cyanamide were the next most widely applied growth regulators. More area was treated with forchlorfenuron (increase of 12,238 acres) and hydrogen cyanamide (increase of 4,415 acres) in 2017. Gibberellins are applied in early spring to lengthen and loosen grape clusters and increase berry size. Ethephon releases ethylene and is used to enhance fruit ripening in raisin grapes and fruit color in table grapes. Hydrogen cyanamide is applied after pruning to promote bud break. Forchlorfenuron is a synthetic cytokinin, applied after fruit set to increase the size and firmness of table grapes.

Walnut

California produces 99 percent of the walnuts grown in the United States. Around 65 percent of the crop is exported to countries such as Germany, Turkey, China, and India. The California walnut industry is comprised of over 4,000 growers who farmed 335,000 bearing acres in 2017 (Table 33 and Figure A-36). According to the 2017 Walnut Objective Measurement Report, the season had satisfactory chilling hours during the winter and spring, but large amounts of rain in some areas left orchards drenched for several weeks (Chilling hours are units used to measure whether a plant has received enough exposure to a certain cold temperature range to trigger various physiological changes needed to produce the crop, such as flowering). The rains waterlogged root systems, followed by a warm season with higher than average insect pest pressure, and heat waves increased use of sunburn protection materials. Walnut production was estimated, depending on the source, somewhere between 615,000 and 650,000 tons in 2017, a decrease of at least five percent from the previous year – likely a result of lower yields per acre.

The price increased by nearly 37 percent while bearing acreage increased by six percent. In addition to the 335 thousand bearing acres, about 65 thousand non-bearing acres may also be treated with pesticides. The amount of applied pesticides increased by nine percent and the acres treated increased by 12 percent (Table 33).

Table 33: Total reported pounds of all active ingredients (AI), acres treated, acres bearing, and prices for walnut each year from 2013 to 2017. Bearing acres are from USDA(d), 2016 - 2018; marketing year average prices are from USDA(d) 2016 - 2018. Acres treated means cumulative acres treated.

The acres treated with insecticides, which includes miticides, increased by 14 percent (Figure 35), although total insecticide pounds decreased by three percent. Important pests for walnuts include codling moth, walnut husk fly, navel orangeworm, aphids and webspinning spider mites. The top five insecticides by acres treated in 2017 were chlorantraniliprole, abamectin, bifenthrin, lambda-cyhalothrin, and methoxyfenozide (Figure 36). Chlorantraniliprole, an anthranilic diamide insecticide for treatment of codling moth, navel orangeworm, and other caterpillars, surpassed abamectin, the previous most used insecticide, increasing 65 percent since 2016. However, abamectin, a miticide, retained second place in the top five insecticides due to its low cost and continued efficacy. The pyrethroid lambda-cyhalothrin joined the top five in 2017, in part due to its inclusion in some products that also contain chlorantraniliprole. Pheromone-treated acreage continued to climb with a 56 percent increase since 2016 (Figures 36 and A-37).

The acres treated with herbicides increased by four percent, a bit less than the increase in bearing acreage (Figure 35). Similar to 2016, glyphosate, oxyfluorfen, glufosinate-ammonium, saflufenacil, and paraquat dichloride were the top five herbicides by acres treated (Figure 36). Lack of availability of glufosinate-ammonium on the west coast in 2014 and 2015 resulted in low use that did not really reflect its high demand at the time. Around 2012, glufosinate-ammonium went off patent, increasing the number of available herbicide products and likely reducing costs due to product competition. Acres treated with glufosinate-ammonium continued to climb, with a 27 percent increase since 2016.

Glyphosate remained the herbicide with the most use due to its effectiveness at controlling a wide variety of weeds and its relatively low cost. However, reports of glyphosate-resistant weeds continue to surface, causing growers to take measures to delay or prevent resistance. The Sacramento Valley is dominated by glyphosate-resistant ryegrass whereas in the San Joaquin Valley, glyphosate-resistant fleabane and horseweed are more prevalent. In both areas, glyphosate-resistant summer grasses such as junglerice are becoming increasingly important problems. Glufosinate-ammonium and paraquat dichloride are non-selective herbicides that are often used in conjunction with a protoporphyrinogen oxidase (PPO) inhibitor such as saflufenacil or oxyfluorfen as an alternative to glyphosate that can slow or prevent glyphosate resistance. Saflufenacil is less expensive than glufosinate-ammonium and controls broadleaf weeds like fleabane and horseweed, but is not effective on grass weeds (Figures 36, A-37 and A-38).

Figure 35, PNG: Acres of walnut treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

The acres treated with fungicides increased 17 percent (Figure 35). Copper and mancozeb, used for blight control, had the highest use, increasing in acres treated by seven and 14 percent respectively. Propiconazole, tebuconazole, and azoxystrobin were also in the top five fungicides for 2017, with propiconazole showing a 41 percent increase in acres treated (Figures 36, A-37, and A-38). These increases were likely due to higher incidence of Botryosphaeria canker (Bot), a disease caused by fungi that can infect branches, nuts, spurs, and shoots of walnut trees, resulting in severe crop loss. Acres treated with the biopesticide potassium phosphite jumped 298 percent to 36,332 acres, possibly due in part to the extension of the European Union's (EU) maximum residue limit (MRL) for phosphite-containing materials. Potassium phosphite treats a wide range of diseases, including Phytophthora. The EU's earlier stricter controls on phosphites were meant to target phosphites such as fosetyl-al, not potassium phosphite, which is thought to have very low toxicity. The extension of the MRL allowed potassium phosphite to be used on walnuts exported to the EU.

Figure 36, PNG: Acres of walnut treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

There were 7,665 acres treated with fumigants in 2017, with little change since 2016. Fumigants make up less than one percent of total walnut acres treated with pesticides, but are 11 percent of total pounds due to the high application rates of fumigant products. The top five fumigants by acres treated included aluminum phosphide, chloropicrin, 1,3-dichloropropene, metam-sodium, and dazomet (Figure 36). Aluminum phosphide, a fumigant used for vertebrate control, had the highest acres treated despite a continuing decrease in acres treated each year, while 1,3-dichloropropene, a soil fumigant, had the largest use in pounds. Chloropicrin took second place in both the top five acres treated and pounds applied. Although pounds of chloropicrin decreased from 2016 by 17 percent, the acres treated increased. Given the cost of, and tighter regulations on, fumigants, some growers practice fallowing or cover-cropping for a year prior to replanting orchards with new trees as an alternative to fumigants.

Wine grape

There are four major wine grape production regions: North Coast (Lake, Mendocino, Napa, Sonoma, and Solano counties); Central Coast (Alameda, Monterey, San Luis Obispo, Santa Barbara, San Benito, Santa Cruz, and Santa Clara counties); northern San Joaquin Valley (San Joaquin, Calaveras, Amador, Sacramento, Merced, Stanislaus, and Yolo counties); and southern San Joaquin Valley (Fresno, Kings, Tulare, Kern, and Madera counties) (Figure A-39). Pest and disease pressure may differ among these regions. The pooled figures in this report may not reflect differences in pesticide use patterns between production regions.

Changes in pesticide use on wine grape are influenced by a number of factors, including weather, topography, pest pressure, evolution of resistance, competition from newer pesticide products, commodity prices, application restrictions, efforts by growers to reduce costs, and increased emphasis on sustainable farming. It is often difficult to isolate which factors explain particular patterns of use.

Table 34: Total reported pounds of all active ingredients (AI), acres treated, acres planted, and prices for wine grape each year from 2013 to 2017. Planted acres are from CDFA(b), 2016 - 2018; marketing year average prices are from USDA(d) 2016 - 2018. Acres treated means cumulative acres treated.

The total pounds of pesticides applied and the cumulative acres treated in 2017 increased by 5.8 and 1.2 percent, respectively (Table 34). The acres treated with sulfur (three percent increase), herbicides (one percent increase), fungicides (two percent increase), fumigants (eight percent increase), and insecticides (six percent increase) increased marginally in 2017. The long-term trend over the last two decades is an increase in acres treated for all pesticide types except for sulfur, which has tended to fluctuate more annually (Figure 37).

The top five insecticides (including miticides) in 2017 included imidacloprid, abamectin, spirotetramat, methoxyfenozide, and oils (Figure 38). Vine mealybug continued to be a concern for growers. Since its first detection in California around 1994 it has spread and it is now found throughout most of the grape growing regions of California. The warm winters since 2012 have allowed vine mealybug populations to build up early in the season. Use of mating disruption has been on the rise over the last few years; lavanduyl senecioate, a mealybug pheromone, was used on 268 percent more acreage in 2017 than 2016. The increase was largely due to registration in mid-2016 of a new spray formulation, which is less expensive than the dispenser-based products. In the North Coast region, the Virginia creeper leafhopper, a recent pest, continued to cause substantial damage in some locations, as did the western grape leafhopper. While there is effective biological control for western grape leafhopper, Virginia creeper leafhopper infestations require insecticide applications. In this region, these leafhoppers have generally been treated with organic materials (botanical pyrethrins and oils) as well as imidacloprid.

Figure 37, PNG: Acres of wine grape treated by all AIs in the major types of pesticides from 1997 to 2017. Text files of data are available.

There has been a generally increasing use of relatively lower risk insecticides (oil, spirotetramat, buprofezin) over the past five years. Over this same period, use of the neonicotinoid insecticides such as imidacloprid, thiamethoxam and clothianidin, have tended to increase, though acres treated with imidacloprid decreased in 2014 and 2016 (Figure 38). These insecticides are used to control mealybugs, leafhoppers and sharpshooters. Use of chlorpyrifos dropped off sharply in 2011 and remained relatively low ever since. Chlorpyrifos was made a restricted material in 2015. Large vine mealybug populations have kept this AI as an important tool for growers however. Chlorpyrifos is used as post-harvest or delayed dormant treatments to prevent spring buildup of vine mealybug populations. Some AIs used for mite control (abamectin, etoxazole, fenpyroximate) increased in acres treated in 2017 while the recently registered cyflumetofen and hexythiazox were used on less acreage; the opposite pattern of what was observed in 2016. Spider mites were a problem in 2017 and growers rotate miticides to manage for resistance. Methoxyfenozide has continued to be used on a substantial area for the treatment of Lepidoptera (caterpillars). Chlorantraniliprole, acetamiprid, and spinosad are less commonly used for Lepidoptera; these AIs were used on a greater amount of acreage in 2017, but no trend is apparent over the longer term. In 2017, Bacillus thuringiensis doubled in acreage treated. Most of the B. thuringiensis applications were in the southern San Joaquin Valley region (especially Fresno and Kern counties).

Overall, fungicide use has been increasing for two decades (Figure 37), though acres treated with the major AIs changed little over the past five years. The top five fungicides by acres treated included copper, quinoxyfen, pyraclostrobin, boscalid, and tebuconazole (Figure 38). The winter of 2016-2017 was wetter in most parts of the state than the previous winters, leading to powdery mildew pressure in some areas. While there were small increases in acres treated with some fungicides (copper, boscalid/pyraclostrobin combination fungicides, tebuconazole, potassium bicarbonate), the decreases in others led to little net change. Fungicides that were registered in the last 2-5 years (fluopyram, cyflufenamid, flutriafol) have been applied on increasing acreage, as might be expected as growers explore new options. A product containing both fluopyram and tebuconazole was registered in 2012 and accounts for increases in applications of these AIs. It is likely that growers were rotating AIs to slow the evolution of resistance. The top five fungicides applied to the largest cumulative treated area changed little from 2016, with tebuconazole replacing myclobutanil for fifth largest in acres treated (Figure 38). Fluopyram was applied to a larger number of acres in 2017 than myclobutanil.

The top five herbicides in acres treated included glyphosate, glufosinate-ammonium, oxyfluorfen, indaziflam, and rimsulfuron (Figure 38). Use of paraquat dichloride and flumioxazin decreased. Indaziflam was first registered in 2011 and its use has generally increased since that time. For a number of reasons, including resistance issues, the acres treated with glyphosate decreased, while a larger area was treated with glufosinate-ammonium. Besides indaziflam, only flazasulfuron was applied to a substantially larger acreage in 2017. They are both pre-emergence herbicides applied in late winter to early spring; a wet winter may have made a likely choice to eliminate key weeds before they become problems in the summer.

Figure 38, PNG: Acres of wine grape treated by the top five AIs of each AI type from 2013 to 2017. Text files of data are available.

The acres treated with fumigants in 2017 was greater than that of the previous year, but still only made up 0.07 percent of the acres treated with all pesticides for wine grapes. The top five fumigants by acres treated included aluminum phosphide, 1,3-dichloropropene, metam-postassium (potassium n-methyldithiocarbamate), dazomet, and chloropicrin, though the last three fumigants in the list were all under 100 acres (Figure 38). A decreasing trend in use of both soil fumigants and aluminum phosphide, used for rodent control, has been observed over the past five years (data not shown).

Gibberellins were by far the most commonly applied plant growth regulator. Use of all plant growth regulators decreased in 2017; plant growth regulators were applied to the smallest number of acres since 2008.

Sources of Information

Adaskaveg, J., D. Gubler and T. Michailides. 2013. Fungicides, bactericides, and biologicals for deciduous tree fruit, nut, strawberry, and vine crops. UC Davis Dept. of Plant Pathology, UC Kearney Agricultural Center, UC Statewide IPM Program. 53 pp. www.ipm.ucdavis.edu/PDF/PMG/fungicideefficacytiming.pdf

Adaskaveg, J. E., H. Forster, D. Thompson, D. Felts and K. Day. 2012. Epidemiology and Management of Pre- and Post-Harvest Diseases of Fresh Market Stone Fruits. Annual research report submitted to the California Tree Fruit Agreement for 2010. 22 pp. https://ucanr.edu/sites/ctfa/year/2010/?repository=46437&a=92530

Alfalfa and Forage News, News and information from UC Cooperative Extension about alfalfa and forage production, https://ucanr.edu/blogs/Alfalfa/

Administrative Committee for Pistachios (ACP). https://acpistachios.org/industry-resources/statistics-archives/

CCTGA. California Tomato Growers Association. http://www.ctga.org/Statistics

CDFA(a). California Department of Food and Agriculture - National Agricultural Statistics Service. California Almond Acreage Report. www.nass.usda.gov/Statistics by State/ California/Publications/Specialty and Other Releases/Almond/

CDFA(b). California Department of Food and Agriculture - National Agricultural Statistics Service. California Grape Acreage Report www.nass.usda.gov/Statistics by State/ California/Publications/Specialty and Other Releases/Grapes/Acreage/Reports/index.php

CDFA(c). California Department of Food and Agriculture. California Agricultural Statistics Review www.cdfa.ca.gov/Statistics/

California Farm Bureau. Ag Alert. Various issues. http://www.agalert.com/

Capital Press. Various issues. https://www.capitalpress.com/

Miranda, M., O. Zanardi, H. Volpe, R. Garcia, N. Roda, E. Prado. 2017. Spray application of different kaolin formulations on sweet orange plants disrupt the settling and probing behavior of Diaphorina citri. Abstracts from the 5th International Research Conference on Huanglongbing. Journal of Citrus Pathology, 4(1). https://escholarship.org/uc/item/2cr0f2kc

Ogawa, J.M. and H. English. 1991. Diseases of Temperate Zone Tree Fruit and Nut Crops. UC ANR, Oakland, Calif. Pub. 3345. 461 pp.

Summers, C.G. and Putnam, D.H. (editors), 2008. Irrigated Alfalfa Management for Mediterranean and Desert Zones.University of California Agriculture and Natural Resources. https://alfalfa.ucdavis.edu/IrrigatedAlfalfa/

University of California Agricultural and Natural Resources Field Notes.

University of California Integrated Pest Management (UC IPM). Pest Management Guidelines. http://ipm.ucanr.edu/

USDA. United States Department of Agriculture - National Agricultural Statistics Service. Crop Progress and Condition Reports. California Crop Weather. (weekly bulletins) www.nass.usda.gov/Statistics by State/California/Publications/Crop Progress & Condition/

USDA. United States Department of Agriculture - National Agricultural Statistics Service. Agricultural Statistics, Annual. https://usda.library.cornell.edu/concern/publications/j3860694x?locale=en

USDA. United States Department of Agriculture - National Agricultural Statistics Service. Quick Stats. http://quickstats.nass.usda.gov

USDA(a). United States Department of Agriculture - National Agricultural Statistics Service. Acreage. https://usda.library.cornell.edu/concern/publications/j098zb09z?locale=en

USDA(b). United States Department of Agriculture - National Agricultural Statistics Service. Citrus Fruits. https://usda.library.cornell.edu/concern/publications/j9602060k?locale=en

USDA(c). United States Department of Agriculture - National Agricultural Statistics Service. Crop Values Annual Summary https://usda.library.cornell.edu/concern/publications/k35694332?locale=en

USDA(d). United States Department of Agriculture - National Agricultural Statistics Service. Noncitrus Fruits and Nuts https://usda.library.cornell.edu/concern/publications/zs25x846c?locale=en

USDA(e). United States Department of Agriculture - National Agricultural Statistics Service. Vegetables Annual Summary https://usda.library.cornell.edu/concern/publications/02870v86p?locale=en

USDA(f). United States Department of Agriculture - National Agricultural Statistics Service. California Processing Tomato Report https://nass.usda.gov/Statistics by State/California/ Publications/Specialty and Other Releases/Tomatoes/

Varela, Lucia G.; Rhonda J. Smith; and Glenn T. McGourty. 2013. Sonoma County Farm News, July.

Weksler, A., A. Dagar, H. Friedman and S. Lurie. 2009. The effect of gibberellin on firmness and storage potential of peaches and nectarines. Proceedings of the VII International Peach Symposium. International Society for Horticultural Science Acta Horticulturae 962. http://www.actahort.org/books/962/962 80.htm

Western Farm Press. Various issues. http://www.westernfarmpress.com/

And many thanks to all the contributions and expertise from County Agricultural Commissioners, growers, University of California Cooperative Extension Area Integrated Pest Management Advisors and Farm Advisors, pest control advisors, commodity marketing boards, and University of California researchers.

Appendix

Text files of data are available.

Figure A-1, PDF: Acres treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-2, PDF: Acres treated by the major AIs and crops in 2017. Text files of data are available.

Figure A-3, JPG: Number of pesticide applications in alfalfa by township in 2017. Text files of data are available.

Figure A-4, PDF: Acres of alfalfa treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-5, PDF: Acres of alfalfa treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-6, JPG: Number of pesticide applications in almond by township in 2017. Text files of data are available.

Figure A-7, PDF: Acres of almond treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-8, PDF: Acres of almond treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-9, JPG: Number of pesticide applications in carrot by township in 2017. Text files of data are available.

Figure A-10, JPG: Acres of carrot treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-11, PDF: Acres of carrot treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-12, JPG: Number of pesticide applications in cotton by township in 2017. Text files of data are available.

Figure A-13, PDF: Acres of cotton treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-14, PDF: Acres of cotton treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-15, JPG: Number of pesticide applications in orange by township in 2017. Text files of data are available.

Figure A-16, PDF: Acres of orange treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-17, PDF: Acres of orange treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-18, JPG: Number of pesticide applications in peach and nectarine by township in 2017. Text files of data are available.

Figure A-19, PDF: Acres of peach and nectarine treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-20, PDF: Acres of peach and nectarine treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available..

Figure A-21, JPG: Number of pesticide applications in pistachio by township in 2017. Text files of data are available.

Figure A-22, PDF: Acres of pistachio treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-23, PDF: Acres of pistachio treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-24, JPG: Number of pesticide applications in processing tomato by township in 2017. Text files of data are available.

Figure A-25, PDF: Acres of processing tomato treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-26, PDF: Acres of processing tomato treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-27, JPG: Number of pesticide applications in rice by township in 2017. Text files of data are available.

Figure A-28, PDF: Acres of rice treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-29, PDF: Acres of rice treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-30, JPG: Number of pesticide applications in strawberry by township in 2017. Text files of data are available.

Figure A-31, PDF: Acres of strawberry treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-32, PDF: Acres of strawberry treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-33, JPG: Number of pesticide applications in table and raisin grape by township in 2017. Text files of data are available.

Figure A-34, PDF: Acres of table and raisin grape treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-35, PDF: Acres of table and raisin grape treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-36, JPG: Number of pesticide applications in walnut by township in 2017. Text files of data are available.

Figure A-37, PDF: Acres of walnut treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-38, PDF: Acres of walnut treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.

Figure A-39, JPG: Number of pesticide applications in wine grape by township in 2017. Text files of data are available.

Figure A-40, PDF: Acres of wine grape treated by the major AIs from 1998 to 2017. Text files of data are available.

Figure A-41, PDF: Acres of wine grape treated by the major AIs by month and AI type from 2014 to 2017. Text files of data are available.