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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

2020 Annual Report

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].

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.

Progress Report
This is the final report for project 0500-00007-109-00D, which will terminate on September 30, 2020. Interregional Research Project #4 (IR-4) field trials have been conducted on projects over the life of the project 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, herbs, field crops, strawberries and prickly pear cactus. Various pesticides have been evaluated in the field test plots on these minor crops. Commercially acceptable, minor crops have been grown each year, and sprayed according to the protocols with various test substances using small plot sprayers that simulate commercial application equipment. Crops were frequently monitored for phytotoxicity from application treatments and timing of sprays. Residue samples were collected at harvest and frozen until shipment to a designated IR-4 analytical laboratory for residue analysis. Eighty-one field trials have been conducted over the life of the project by ARS in Salinas, California. These trials have involved various fungicides, insecticide, nematicides, herbicides and plant growth regulators. The majority of the IR-4 projects were designed for crops grown commercially outdoors, but there were two trials designated for greenhouse use. One trial was a plant growth regulator to assist greenhouse growers for control of plant height on broccoli transplants. Another was a fungicide trial on celery transplants, intended to control Pythium root rot, due to the importance of transplants for commercial celery production. Vegetable projects accounted for most of the field trials, totaling 65, for the IR-4 Program. Cool season vegetables trials have consisted of cole crops (broccoli and cabbage), green bunching onion, asparagus, spinach, lettuce (leaf and head), mustard greens, leek, garden beets, radish, snap beans and carrots. A few warm season vegetable trials have been with summer squash, lima beans, dry bulb onions and bell peppers. During the life of the project, various pesticides have been tested on these vegetable crops to manage a variety of pest problems that growers commonly encounter during their commercial production. Herb trials were assigned for two of the five years of the project. Two parsley trials were sprayed with a fungicide to control Septoria leaf spot and both fresh and dried samples were collected for residue analysis. One parsley trial was a decline study to determine how the fungicide breaks down over time in the parsley plants. Basil is prone to downy mildew, which is a destructive disease on this crop, so new fungicide chemistries are needed for optimal control in the greenhouse and field environments. Three field trials were conducted on stevia, utilizing three different fungicides for control of Septoria leaf spot, one of the most important pathogens of stevia. Stevia is harvested for the leaves and utilized as a sugar substitute, but Septoria can completely defoliate plants prior to harvest, leading to huge yield losses. Currently there are no fungicides registered for stevia and having products to manage this pathogen are critical to expanding production of this crop in the United States. Field crop projects consisted of two dry bean crops grown for shelling. One trial was a herbicide project with the material applied pre-planting for weed control and the other one was a fungicide trial for control of Cottony Leaky caused by Pythium. Strawberry trials were undertaken during three different years on four projects with a commercial cooperator. One was a fungicide trial for the control of Phytophthora species and Pythium. Another was an insecticide trial for lygus control, which causes a deformity on the fruit known as cat-facing. For the nematicide trial, the material was applied as a drench to newly planted annual strawberries within one week of transplanting. The herbicide trial was intended to control the weed green kyllinga and was banded in the furrows. Prickly pear cactus projects were conducted during 2017 with a local commercial grower. These four insecticide trials, using the material flonicamid, were aimed at controlling concineal scale insects. Wind-blown cochineal infestations, when left uncontrolled, cause cactus orchards to be destroyed, resulting in huge financial loses for growers. With only one insecticide currently registered on cactus (Carbaryl) and another insecticide pending label approval by the Environmental Protection Agency (Sivanto), additional insecticides from different classes are needed to provide economic control. The prickly pear cactus trial plants were sprayed three times, at seven-day intervals and a one-day phi (pre-harvest interval), with both the pads and fruit harvested for residue analysis.