Black Cutworm

Agrotis ipsilon

Black cutworm beside the corn plant it cut off
Black cutworm beside the corn plant it cut off. Photo courtesy of W.M. Hantsbarger. Licensed under CC BY 3.0.
Black Cutworms have a very widespread distribution and can be a singificant pest of corn, soybeans, grains, and other crops. Cutworms get their name from their practice of chewing on seedlings at the soil surface, cutting the plant off at its base. Black cutworms are the most serious of the cutworms, with a single larva able to cut off several plants.
Black cutworms are grey or black in color with a brown head. Each body segment has several dark bumps.
Black cutworn on a corn leaf
Black cutworm on a corn leaf. Photo courtesy of Adam Sisson. Licensed under CC BY 3.0.
Adult moths are brown in color and have a dark "dagger" shape on the back of each wing (circled in red).
Black cutworm adult moth with the identifying dagger marks circled in red
Black cutworm adult moth. Note the dagger marks circled in red. Photo courtesy of Adam Sisson. Licensed under CC BY 3.0.
Black cutworms are the most damaging of the cutworms, and a single larva can cut several plants. This can lead to a significant stand loss and reduced yields.
Insecticides can be used to treat black cutworms. The decision to control should be based on the number of cutworms and the ability of surrounding healthy plants to compensate for the missing plants. Always read and follow all label instructions.
Some, but not all Bt traits provide protection against black cutworm. In cases of heavy infestation, even crops with Bt traits may require other treatment options.