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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Research Project #438829

Research Project: Minor Use Pesticide Testing on Vegetables and Sugar Crops

Location: Crop Improvement and Protection Research

2021 Annual Report

Objective 1: Conduct laboratory and field tests to provide residue data needed to establish a tolerance on a specific commodity or to support a crop group tolerance.

Research to support registrations of minor use pesticides. Apply pesticides according to IR-4 protocol guidelines. Obtain performance data, phytotoxicity, yield, and efficacy from treated and untreated field plots. Ship samples to laboratories for residue analyses. Protocols will be employed using appropriate Standard Operating Procedures and conducted under provisions outlined in 40CFR part 160 in accordance with EPA's Laboratory Practice Standards.

Progress Report
This report documents progress for project 0500-00007-121-00D, which started in October 2020 and continues research from project 0500-00007-109-00D, "Minor Use Pesticide Testing on Vegetables and Sugar Crops." Interregional Research Project #4 (IR-4) field trials have been conducted on projects during fiscal year (FY) 2021 according to approved protocols developed by IR-4 Project Headquarters. Following local good agricultural practices for agricultural production, field testing has been done on vegetables and herbs. Commercially acceptable minor crops have been grown and sprayed according to the protocols with test substances using small plot sprayers that simulate commercial application equipment. Various pesticides will be evaluated in the field test plots on these minor crops. Plants will be frequently monitored for phytotoxicity from application treatments and timing of sprays. Residue samples will be collected at harvest and frozen until shipment to a designated IR-4 analytical laboratory for residue analysis. During FY 2021, five projects are being conducted on fresh market tomatoes for both small and large fruit. Three trials are with the fungicide, pyraziflumid, for control of southern blight (Sclerotium rolfsii) made by drench and drip applications. Two trials are monitoring the effectiveness of the herbicide, flumioxazin and pyroxasulfone, to control weeds, including common purslane, pigweed and sedges found in tomato production. Two fungicide projects are being undertaken during FY 2021. One trial is with basil to control downy mildew using the fungicide, fluoxapiprolin. Three foliar sprays will be made at seven-day intervals with a zero-day pre-harvest interval (PHI). Fresh and dried samples will be collected. Another project is with the fungicide, difenoconazole and azoxystrobin, on spinach to control the foliar disease Stemphyllium. The herb, stevia, is being grown for fresh and dried samples and the herbicide, linuron, will be applied over the winter when the plants are dormant. The goal is to control winter annual and biennial weeds in commercial stevia production. Two carrot projects, in cooperation with Agriculture and Agri-Food Canada, will study the magnitude of the residue from the fungicide, oxathiapiprolin and mandipropamid. This material will be applied in four broadcast foliar applications at seven-day intervals and with a seven-day PHI. One carrot trial is a decline study to see how the fungicide breaks down over time.