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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Research Project #429522

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

Location: Crop Improvement and Protection Research

2017 Annual Report

1a. Objectives (from AD-416):
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. [NP 304, C2, PS 2A3 and C3, PS 3A2].

1b. Approach (from AD-416):
Research to suppport 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 accordances with EPA's Laboratory Practice Standards.

3. Progress Report:
Interregional Research Project #4 (IR-4) field trials are being conducted on 17 projects according to approved protocols developed by IR-4 Project Headquarters. Following local good agricultural practices for crop production, field testing is in progress on cool season vegetables, herbs and prickly pear cactus. A variety of pesticides are being evaluated in the field on these minor crops. Commercially acceptable minor crops are being grown and sprayed according to the protocols with various test substances using small plot sprayers that simulate commercial application equipment. Crops are frequently monitored for phytotoxicity from application treatments and timing of sprays. Residue samples are collected at harvest and frozen until shipment to a designated analytical laboratory for residue analysis. This season, four field trials are being conducted with the herbicide Caparol on spinach, broccoli and cabbage as a plant-back study. A plant-back restriction on an herbicide label limits how soon a rotational crop can be planted following registered crop use on a labeled crop. These rotational crops, spinach, broccoli and cabbage, will be planted at both 60- and 90-days after Caparol is sprayed at the registered label rate on a cilantro crop. The goal is to shorten the plant-back interval for these rotational crops listed on the Caparol label and provide crop safety data to the manufacturer. Leaf and head lettuce are susceptible to lettuce drop disease caused by fungus Sclerotinia minor and Sclerotinia sclerotiorum. Four trials are ongoing with the fungicide mandestrobin, applied as two foliar directed sprays at emergence and 10 days after thinning. One of these four trials will be a decline study, designed to evaluate the residue levels over time, when the crop is harvested 7- and 3-days prior to the projected harvest date, followed by sampling 3- and 7-days after the target harvest date. Two fungicide trials are being conducted on parsley for fresh and dried samples. Growers need additional fungicides to adequately control Septoria leaf spot, caused by the fungus Septoria petroselni. Difenoconazole fungicide will be applied twice, with a 14-day interval between sprays, and a pre-harvest interval (PHI) of 14-days. One of these two trials will be a decline study on the fresh sample, collecting the first sample on the same day as the second spray. Additional samples will be collected 3-, 7-, 14- and 21-days later. An insecticide trial is planned on green bunching onions using ISM-555, an unregistered insecticide with the U.S. Environmental Protection Agency (EPA), for control of thrips insects. Three applications of this insecticide will be made at 7-day intervals, with a 7-day PHI for harvest. The fungicide ethaboxam is used for the control of two fungal diseases, downy mildew caused by the fungus Peromospora parasitica and Pythium, on mustard greens and cabbage. The crops will receive two applications of this fungicide at 7-day intervals with a 2-day PHI for harvest. In the fall, four insecticide field trials are planned on prickly pear cactus with a local commercial grower. They will use the material flonicamid for control of cochineal scale insects. Wind-blown cochineal infestations, when left uncontrolled, can destroy cactus orchards, resulting in huge financial losses for growers. With only one insecticide currently registered on cactus (Carbaryl) and another insecticide pending label approval with the EPA (Sivanto), additional insecticides from different chemistry classes are needed to provide economic control of these insect pests. The prickly pear cactus trial plants will be sprayed three times, at 7-day intervals and a 1-day PHI, with both the pads and fruit harvested for residue analysis. The Salinas field site will manage approximately 20 to 25 field residue trials on minor use crops each year over the next five years. The facility will provide treated and untreated samples to the IR-4 laboratories for residue analysis, while continuing to produce quality scientific data in order to meet EPA's Good Laboratory Practice requirements for the IR-4 Program. The same milestones will be utilized over the five year period.

4. Accomplishments