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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Research Project #444427

Research Project: Antagonistic Interactions between Insecticides, Fungicides and Foliar Nutrient Blends Compromise the Efficacy of Tank Mix Partners

Location: Vegetable Crops Research

Project Number: 5090-21220-006-040-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2023
End Date: Jul 31, 2024

1.) Determine if mixtures of biorational pesticides and nutritional supplements that are labeled for and used to control Colorado Potato Beetle (CPB) and early blight (Alternaria solani) in potato results in reduced efficacy (antagonism) using field-based bioassays, and 2.) evaluate for potential antagonism in the control of select diseases including late blight (Phytophthora infestans) and A. solani using detached-leaf bioassays under controlled, laboratory-based conditions.

Objective 1. Field based bioassays measuring antagonism (Cooperator). Four insecticides will be screened in two- or three-way combinations with fungicides and foliar nutrients and the effects of the combinations in the control of CPB will be uncovered. Similarly, fungicides will be evaluated in two- and three- way interactions with insecticide and foliar nutrient mixes to observe effects on A. solani occurrence and associated disease development. These four insecticides will be used in the study: spinetoram, abamectin (Syngenta), abamectin (FMC) and dsRNA. Similarly, the fungicides: chlorothalonil, mancozeb, boscalid, and difenoconazole will be employed. The Foliar-applied nutritional components will include the following five micronutrient mixes: BioGrow 3-12-0, BioForge, NUE Mag, Max Set 28 and SetMore Base. Test plots will be maintained according to standard commercial practices including herbicide, and irrigation management. Objective 2. Detached leaf bioassays to investigate the performance of pesticide mixtures (ARS). Cut whole leaves from mature S. tuberosum cv. Russet Burbank will be used to perform detached leaf assays (DLA) to test for infection and lesion growth following inoculation with P. infestans. Leaves will be cut to a uniform length (6-8 inches) and dip inoculated with a set of pesticide mixtures similar to those described previously in Obj. 1. The following fungicides: chlorothalonil, mancozeb, oxathiapiprolin, and mandipropamid will be tested. Infection and lesion size of P. infestans and A. solani inoculations on whole leaves pre- treated with these fungicides individually Leaves will be visually scored for the appearance of symptoms using ImageJ software five days after inoculation.