Department of Pesticide Regulation

Environmental Monitoring and Pest Management

1020 N Street, Room 161

Sacramento, California 95814-5624

Protocol for Development of Methodologies to Measure Deposition Residues of

SureDye  Applied for Eradication of Mediterranean Fruit Fly

April 12, 1996

INTRODUCTION

In the past, emergency eradication programs for the Mediterranean Fruit fly (Medfly) have involved the aerial application of a malathion-bait mixture over large regions of farming and residential properties. A food dye (SureDye) and bait mixture is being evaluated as a replacement for malathion. Recently, promising results have been found with applications of the SureDye  mixture in trials performed by the United States Department of Agriculture (USDA) in Hawaii. During the spring of 1996, the California Department of Food and Agriculture's (CDFA) Pest Detection and Emergency Projects branch will be conducting a trial aerial application of SureDye  and bait to assess its pesticide efficacy. Prior to application, sterile Medflies will be released in a selected orchard in Orange County and the fly population will be monitored through trapping. The SureDye  and bait mixture will be applied by helicopter as an ultra-low volume spray at weekly (6 to 8 day) intervals and will continue for up to 8 applications. The dye concentrations in the preliminary test in Hawaii were much less than the malathion concentrations currently used in aerial malathion-bait sprays.

SureDye  is a mixture of Red Dye #28 and Yellow Dye #8, both of which are xanthene dyes registered for use as color additives in drugs and cosmetics by the U.S. Food and Drug Administration. Scientists speculate that the red dye reacts with light and is transformed into a substance that destroys the insect's digestive tract. The yellow dye is believed to increase the activity of the red dye. The SureDye  compounds degrade rapidly under sunlight and application of SureDye  is not likely to cause significant impacts on the environment. The reported half life of the dyes is approximately 1 hour under sunlight. Neither dye persists for more that a few hours in air or water due to rapid photodegradation.

This study will be conducted as a two-phase project. The first phase will involve the initial development of the appropriate sampling and analytical methodologies. The second phase will consist of comprehensive sampling during application and analysis of samples.

OBJECTIVE

A. Develop and validate analytical methodologies to measure residues of SureDye  product.

B. Measure the amount of SureDye  reaching the ground from the trial aerial application conducted by CDFA under an experimental use permit.

PERSONNEL

This study will be conducted by the EHAP, under the general direction of Roger Sava.

Key personnel are:

Project Leader: Pam Wofford

Statistical Consultation: Rosie Gallavan

Senior Staff Scientist: John Troiano

Field Operations: Adrian Bradley, Pam Wofford

Lab Liaison/Quality Assurance: Nancy Miller

Chemical Analysis: Paul Lee

Contact Person: Madeline Brattesani

Question concerning this monitoring should be directed to Madeline Brattesani at (916) 324-4100; fax, (916) 324-4088; e-mail, mbrattesani@cdpr.ca.gov.

SAMPLING AND ANALYTICAL METHODS DEVELOPMENT

Develop Analytical Methods -

The primary analytical laboratory for this study will be the California Department of Food and Agriculture's Center for Analytical Chemistry. Analytical methods will be developed for residue analysis of SureDye  on deposition sampling media, such as steel sheets and deposition sheets (Kimbies). The method detection limit, reporting limit and storage statistics will be determined for all media tested. The method detection limits will be determined using U.S. EPA procedures. In addition to providing an estimate of the detection limits and storage stability, these analyses will give preliminary information on the precision, accuracy, interferences and costs that will be associated with each method.

Determine Media of Interest - A survey of deposition sampling media, such as deposition sheets (Kimbies) and steel sheets, to quantify deposition will be conducted to determine the best possible media for chemical extraction and analytical quantification.

Sampling -

Following methods development, sampling will be conducted during the trial aerial application conducted by CDFA. SureDye  concentrations on the selected media will be measured. The results will be used to determine amount of SureDye  reaching the ground.

Mass Deposition - 30 sites within the treatment area will be sampled during application to determine the amount of pesticide reaching the ground. Site selection will be random; however, sites selected will be reviewed so that covered areas and locations on the edges of the treatment area will be avoided. Samples will be collected immediately after spraying, when spray droplets are sufficiently dry. Because of the rapid photodegradation of SureDye , all samples will be covered and protected from exposure to sunlight.

Depending on results from methodology development, other media may be sampled to determine SureDye  concentrations in air, water, soil or vegetation. Sampling to establish dissipation rates may also be conducted if warranted.

QUALITY ASSURANCE/QUALITY CONTROL

All samples will be analyzed for SureDye  by the California Department of Food and Agriculture's Center for Analytical Chemistry.

DATA ANALYSIS

Mass deposition will be presented as mean micrograms per square foot for the treatment area. The number of significant figures reported in final results will be determined by examining both analytical and measurement variability. No other formal statistics will be done. Concentrations measured on other media will be presented as raw data.

TIMETABLE

Methods Development: April 1996

Sampling and Analysis: May 1996

Report Preparation: June - August 1996