In-Field Bt Corn Resistance Found In Two States

Following reports of high levels of corn damage in Iowa, lab studies this summer revealed resistance to Bt hybrids expressing the Cry3Bb1 toxin, found in Monsanto hybrids targeting rootworms.

Field locations where resistance was documented were characterized by high rootworm pressure, with a history of continuous Bt corn planting, says Iowa State University entomologist Aaron Gassman. While this wasn’t considered a widespread threat, Monsanto says it’s working with Gassman on how to handle the apparent resistance.

University of Illinois Extension entomologist Mike Gray also verified severe corn rootworm pruning on some Bt hybrids that express the Cry3Bb1 protein in northwestern Illinois.

The fields were in continuous corn production for many years and producers relied upon Bt hybrids that expressed Cry3Bb1 protein as their primary protection against western corn rootworm injury.

Gray urged no-tillers to be cautious in their choice of hybrids offering corn rootworm protection.

“Many producers have utilized a single-tactic approach for too many years,” he says, “and now unfortunate consequences are beginning to emerge.”


  • AGCO Application Equipment introduced three new RoGator high-clearance sprayers for 2012. The RoGator RG900, RG1100 and RG1300 models have Tier 4 interim-compliant AGCO POWER 8.4-liter diesel engines with e3 selective catalytic reduction (SCR) technology.
  • Beck’s Hybrids has purchased the former Pfister Hybrids facility in El Paso, Ill., to obtain additional seed-processing capabilities, expanded warehouse space, and additional space for research and testing.
  • Nebraska-based Kugler Co. and Wisconsin-based Hydrite Chemical Co.
    signed an agreement to provide a more reliable supply of…
To view the content, please subscribe or login.
 Premium content is for our Digital-only and Premium subscribers. A Print-only subscription doesn't qualify. Please purchase/upgrade a subscription with the Digital product to get access to all No-Till Farmer content and archives online. Learn more about the different versions and what is included.

Top Articles

Current Issue


No-Till Farmer

Get full access NOW to the most comprehensive, powerful and easy-to-use online resource for no-tillage practices. Just one good idea will pay for your subscription hundreds of times over.

Subscribe Now

View More

Must Read Free Eguides

Download these helpful knowledge building tools

View More
Top Directory Listings