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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Research Project #431510

Research Project: Evaluating Parameters of the High Dose Refuge Strategy that are Inadequate for Delaying to Transgenic Corn Among Ear-Feeding Lepidoptera

Location: Corn Insects and Crop Genetics Research

Project Number: 5030-22000-018-11-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2016
End Date: Jul 31, 2019

Objective:
To quantify the level of Bacillus thuringiensis (Bt) toxin resistance among larvae in western bean cutworm populations across different geographic regions, and estimate the toxin exposure received when larvae feed upon different tissues of Bt corn plants over time. Use these data to evaluate the effects of low-dose Bt toxin exposure on rate of selection within natural populations and determine any implications on current insect resistance management practices.

Approach:
Western bean cutworm eggs will be collected by collaborators from different regions where Bt toxin resistance is known to occur. Laboratory bioaassys performed at ARS will be using pure toxin and plant tissues to estimate survivorship at different toxin levels or when exposed to different plant tissues, and estimate any significant differences between resistance levels between populations. Additionally, Bt corn tissue assays will be used to estimate both the relevant exposures encountered by larvae in the field, and predict the variation in mortality among larvae with different resistance alleles when exposed to different plant tissue. All assays will be performed on newly hatched and late instar larvae.