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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Research Project #445381

Research Project: Advancing insect pest management for soybeans: Combating the soybean gall midge and restoring susceptibility to insecticide resistant insects

Location: Corn Insects and Crop Genetics Research

Project Number: 5030-22000-019-013-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2022
End Date: Sep 30, 2025

Objectives of this research are to: 1) develop a novel control strategy using RNA interference (RNAi)-mediated knockdown of transcripts from resistance alleles as a means to restore soybean aphid susceptibility to pyrethroids among known resistant genotypes currently in laboratory colonies; 2) assess the ability of RNAi to increase pyrethroid susceptibility among resistance soybean aphids, and 3) develop an economic model exploring the feasibility of RNAi as a tool of soybean aphid control.

Preliminary laboratory results show that topical application of a double stranded RNA (dsRNA) molecule reduces the level of soybean aphid resistance to pyrethroid insecticides by a corresponding reduction of transcripts from the resistance gene. This RNAi molecule and variations thereof, will be applied to aphids with known genotypes of the resistance allele and varying levels of pyrethroid resistance infested onto soybean plants. Furthermore, this RNAi application will be done in a foliar spray simulator facility with and without concurrent treatment with a pyrethroid insecticide. These comparisons will be made in the laboratory for colony and field-collected aphids. Impacts of RNAi on resistance will be analyzed to estimate the lethal concentration (LC) resulting in 50% (LC50) and 99% (LC99) mortalities for each RNAi molecule, and corresponding reductions in the expression of resistance genes will be made by relative real-time polymerase chain reaction (PCR) assay of aphids sampled from each treatment group.