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Field Crops Entomology Program
Michigan State University
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Hot Topics
Hot Topics
Bt trait table updated for the New Year.
It is a new year, and time to update the Handy Bt Trait Table once again. This latest version adds VT Double Pro Complete and Agrisure Refuge Renew. If you prefer, we also have the table as a single-page handout.
Corn rootworm resistance to Cry3Bb
In July 2011, researchers from Iowa State University published results of a study showing increased survival of corn rootworm beetles from 'problem' fields on Bt rootworm corn expressing Cry3Bb toxin. Cry3Bb is the Bt found in Yieldgard RW and VT triple, as well as one of the Bt toxins in SmartStax. Growers had reported severe lodging and root damage in problem fields for several seasons. These fields had been planted to Cry3Bb rootworm corn for three or more consecutive years. Beetles from control fields - fields with no reports of damage - were still susceptible to Cry3Bb. Beetles from both problem and control fields were also still susceptible to Cry34/35, the Bt used in Herculex RW. The Iowa study is the first laboratory evidence to suggest field-evolved resistance by rootworms to Bt corn. As a result, in the future growers in some areas may have to rethink rootworm management by rotating Bts, going back to soil insecticides, or adding other crops back into the rotation. Meanwhile, EPA is taking a close look at how the seed industry responds to field cromplaints and monitors for resistance.
See the paper entitled 'Field-evolved resistance to Bt maize by western corn rootworm' in the journal PLoS ONE.
You can go directly to the web site by clicking here.