An official website of the United States government.

We've made some changes to If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Corn Rootworm Resistance Monitoring Studies Submitted to EPA

Bt corn registrants are required to submit annual resistance monitoring reports for corn rootworm (CRW). These reports have generally addressed two objectives:

  • bioassay results of CRW populations sampled from random locations in the Corn Belt; and
  • the results of investigations into unexpected  CRW damage to Bt corn fields.

As of 2016, EPA no longer requires the annual monitoring of populations randomly collected from the Corn Belt. Instead, registrants are required to submit a report detailing unexpected damage investigations.  View more information on the resistance monitoring program for CRW

The table at the link below lists the resistance monitoring reports received by EPA. Individual studies are identified by MRID numbers.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.