December 02, 2023

Black cutworm threat in Midwest

Learn what to watch out for

CHATHAM, Ill. — Farmers should keep an eye out for black cutworm — an aggressive pest that arrives in the Corn Belt in late spring, feasting on many plants including corn.

The pest does not overwinter in Midwest fields; however, it blows in from the south when spring storms hit.

In A Nutshell

• Small larvae chew holes in leaves.

• Fourth stage or older larvae exceed the width of a dime in length and can begin cutting V1 to V5 stage plants.

• Drilling into V6 to V8 stage plants can kill growing point.

“It’s black cutworm that we worry about,” said Matt Montgomery, Pioneer field agronomist in Illinois.

“If you’re seeing heavy cutworm pressure, you need to strongly consider fall weed control. Farmers have less and less time in the spring to clean up fields and spray for pests. It’s absolutely critical to start clean and stay clean.”

Management Tips

• Scouting for cutting damage and digging fields is the best way to identify a potential issue.

• Applying a rescue treatment is the most effective and economical way to control black cutworm populations once identified.

• Broadcast pesticide or bait application may be used as a rescue treatment in cases of higher pest pressure and crop damage.

• Utilizing products with traits that provide cutworm protection are the best way to proactively deal with black cut worm. Insecticide seed treatments at high rates may give some control, but lower rates are not as effective.

If fields have a history of black cutworm pressure, they are more likely to have repeat instances.

In these cases, growers should monitor moth flight reports, consider reducing tillage and eliminate other practices that leave a food source for the young larvae, Montgomery said.

Erica Quinlan

Erica Quinlan

Field Editor