Now that northern corn rootworms resistant to Bt-proteins have been found in North Dakota, you’ll want to take steps to keep resistance populations out of your fields.

Janet Knodel, North Dakota State University Extension agronomist, recommends these nine steps:

1. Rotate fields annually between corn and non-host crops such as soybean, flax, sunflowers or wheat.

2. Control volunteer corn that could serve as hosts for local Bt-resistant rootworm populations.

3. Plant non-Bt corn hybrids and use a soil insecticide, especially when low rootworm pressure is expected.

4. Plant non-Bt corn as a refuge, according to guidelines for your Bt corn hybrid.

5. Rotate fields with Bt corn hybrids that have different modes of action each year.

6. Plant Bt pyramided corn hybrids. They contain two or more Cry proteins with different modes of action for control of corn rootworms.

7. Scout fields for corn rootworm adults and assess larval root-feeding injury during late summer.

8. If you experience higher pressure of corn rootworms in your field, report it to your local seed company representative and your local county extension agent / extension entomologist.

9. Stay on top of what’s happening. For more information, see the North Dakota State University Extension publication “E1852 Integrated Pest Management of Corn Rootworms in North Dakota.”

Source: NDSU Extension Service, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.