Pest Management Research Grants Awarded 2017
- Alternatives to soil fumigants in California's
fresh market carrot production
Root knot nematodes (RKN) are the primary cause of plant disease problems in California carrot production. Their wide host range, absence of RKN resistant carrot cultivars, and lack of effective non-fumigant nematicides, biocontrol products or cultural practices have resulted in 40% of the carrot fields being fumigated. There is considerable interest by stakeholders and regulatory agencies in effective, affordable and ecologically more benign alternatives to soil fumigants.
This project will implement an alternative two-step approach that initially will lower RKN population levels with a RKN-resistant crop (e.g. RKN resistant processing tomato cultivars), followed by application of novel non-fumigant nematicides (conventional) or mustard seed meal (organic production).
Key activities of the project will consist of comparing the effect of rotating carrots with a nematode resistant vegetable cultivar compared to a susceptible crop. The efficacy of novel nematicides and mustard seed meal will be determined and compared to controls. Data on the RKN soil population levels, on nematode associated root-symptoms, and on (marketable) yields of the two different crops (tomato, carrots) will be collected. In order to evaluate the financial aspects of the approach, relevant cost estimates will be obtained from the carrot industry.
These practices are more environmentally benign than current soil fumigation practice. These effective, economically and ecologically advantageous IPM systems will eliminate many regulatory requirements, improve air quality, and mitigate public health concerns.
- Utility of Brassica crops for nematode suppression by
biofumigation and co-cropping in walnut orchards
Walnuts are damaged by a number of plant-parasitic nematodes. Pre-plant soil fumigation with methyl bromide and 1,3-D containing compounds have mitigated the damage by these soil dwelling parasites. After the ban of methyl bromide and the environmental and health concerns about 1,3-D, alternative nematode management options are urgently needed.
The use of Brassica cover crops resistant to several plant-parasitic nematodes has been established as a nematode suppression tool. The overall goal of the project to determine the potential benefit of using Brassica inter-crop and cover crops for suppression of plant-parasitic nematodes in a pre-plant and in-orchard strategy.
This project will test biofumigation, where Brassica plants are shredded at flowering, finely ground, and incorporated into the soil. In subsequent decomposition, nematode toxic compounds are released into the soil. Additional nematode suppression can occur during the growing period of the crop via root exudates. The Brassica crops will be used as cover crops during orchard pre-plant periods as a biofumigation approach, and during establishment of new orchards as well as in mature walnut plantings.
These strategies will contribute to the sustainability of the cropping system while reducing the environmental footprint of walnut production.
Media contact: Andreas Westphal, Principal Investigator, 559-646-6555, Andreas.Westphal@ucr.edu or Media Relations, 951-827-6397
- New Fruit Fly Attractants to Reduce Pesticide use in
In California, outbreaks of fruit flies (family Tephritidae) threaten an industry worth $40-billion annually. To monitor populations of these pests, California Department of Food and Agriculture (CDFA) deploy and maintain more than 63,000 traps statewide, most of which are baited with attractants. In response to pest outbreaks, CDFA works in concert with USDA to supplement the trapping network and implement quarantine protocols, which typically require that host fruit be treated with organophosphorus pesticides, such as malathion.
This project aims to develop potent attractants for key fruit fly pests of California agriculture. While some trap lures are highly attractive, others need major improvement. One objective of this project is to test the attractiveness of Mexican fruit fly, Anastrepha ludens, pheromones, epianastrephin and anastrephin, with a goal of commercial development. A second objective is to synthesize structural analogs of known pheromones, so that they can be subsequently evaluated for attractiveness. Specifically, the project will develop new synthetically-accessible attractants for medfly, Ceratitis capitata based on structural motifs found in alpha-copaene and ceralure, two highly attractive and efficacious lures that are currently too costly for commercial applications.
The use of potent attractants in trapping schemes for early detection and population suppression provides a critical opportunity for reducing, or altogether eliminating, the use of organophosphorus pesticides in an eradication program.
Media contact: Spencer Walse, Principal Investigator, 559-596-2750, firstname.lastname@example.org or Sandra Avant, Public Affairs Specialist, Room 1-2220-A, 5601 Sunnyside Ave., Beltsville, MD 20705 -5128, 301-504-1627, Sandra.Avant@ars.usda.gov
- Development of site-specific management of soil
pests using molecular quantification, remote sensing, and field scouting
The soilborne pathogens Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora species, and Verticillium dahliae have emerged or re-emerged as serious threats to strawberry production throughout California with the phase-out of methyl bromide. In strawberry production the current standard practice is to fumigate the whole field at uniform rates to control all pathogens. Because soilborne plant pathogens are typically distributed in an uneven, "patchy" fashion, however, this practice needlessly fumigates areas with little or no disease pressure.
The goal of this project is to develop a zone-based precision fumigation system in which the amount of fumigant to be applied is proportional to the density of soilborne pathogens within that zone.
To do this, levels of soilborne pathogens will be quantified using molecular and plating assays and mapped within selected fields and used to develop a site-specific pre-plant treatment plan. A combination of field scouting, yield, and remote sensing data will evaluate the effectiveness of the preplant treatment and inform the treatment decisions for the following crop season.
By accounting for the typically uneven spatial distribution of soil pathogens, methods developed in this research could maintain disease management efficacy while reducing overall fumigant use and advance practices toward the long-term objective of true integrated management of soilborne diseases.
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