Assay to Measure Rootworm Resistance to Transgenic Maize
Iowa State University Research Foundation
posted on 02/28/2011
Iowa State University researchers have developed a bioassay that can be used to monitor western corn rootworm populations for resistance to Bt corn.
Resistance monitoring for agricultural pest populations
- Replicates natural toxin production
- Allows complete development of the insect
The western corn rootworm is among the most damaging pests for corn crops. Control costs and economic losses together total over $1 billion annually in the US. However, the western corn rootworm is able to overcome to conventional strategies, such as crop rotation and small molecule insecticides, for preventing rootworm damage though its ability to develop resistance. While some soil insecticides still afford acceptable protection levels, their potential to cause environmental damage and human health risks have lead to the development of transgenic corn lines expressing Bacillus thuringensis (Bt) toxin genes for rootworm control. As more and more transgenic corn with the Bt is grown in the US, the ability to monitor pests for resistance becomes increasingly important. However, currently used assays methods (e.g., diet bioassay or sub-lethal seedling assay) can produce ambiguous results because of mold contamination, incomplete larval development, and surface only application of the toxin that can allow the insect to chew through the substrate and be unaffected for the duration of testing. To overcome these drawbacks, ISU researchers have developed a novel assay to measure rootworm resistance to transgenic maize that can be used to screen field populations for their level of resistance to current Bt technologies as required by the EPA. In addition, this assay may also have utility for testing pest populations against newly developed transgenics.
File Number: ISURF #3849
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