Black Cutworm

Black cutworm insects overwinter in Mexico and Texas and are carried north to our region by storm systems from the south between February and June. These same storm systems can make field work in the spring difficult and, in some cases non-existent, allowing winter annual plants to continue to grow and create a favorable environment for the moths to lay eggs.

Identification:

Mark Dreiling, Bugwood.org

Black cutworm moth is identified by the dagger shaped marking on the forewing, which is circled in the picture

Roger Schmidt, University of Wisconsin Madison, Bugwood.org

Black cutworm larvae can be found are dark in color and can be found under soil clods, debris or 1 to 2 inches below the soil surface. These larvae can be 1/8^th in to 2 inches in length.

Areas to monitor: No till and reduced tillage fields especially those with dense vegetation of broadleaf weeds.

Scouting: Damage can appear as notched leaves which is done by younger larva and clipped plants that will have been cut at the soil surface. When assessing this damage, choose five random areas of the field and count 20 plants in those areas. If 3 to 5 percent of these plants show signs of black cutworm feeding and two cutworms can be found, control with an insecticide may be warranted.

Damage from a small cutworm.

Clemson University - USDA Cooperative Extension Slide Series , Bugwood.org

Damage from a more mature cutworm larvae, note the “clipped” plant at the soil surface.

Weedy areas of a field are the main areas to be concerned with at this time. When corn planting begins again, and herbicide applications start to diminish, the current food source for the cutworm larvae, we could start to see feeding in our corn plants. All versions of the Optum AcreMax®, PowerCore® Enlist®, Vorceed® Enlist® Qrome®, and SmartStax® branded products can provide control to smaller larvae, but larger larvae may still warrant further control measures.

Contact your Dairyland Seed DSM or Regional Agronomist for more information.