Figure 1. Army cutworm. Figure 2. Army cutworms are brownish-black and can be found in the soil around the crowns of the plants during the daytime. Figure 3. Damage from army cutworm, which feeds at night on foliage on the soil surface.

Scout for army cutworms in alfalfa and wheat; new generic treatments available

Army cutworms (Figures 1 and 2) can be serious pests of wheat and alfalfa. The eggs are laid in the fall, then hatch and the larvae feed for a short time and then overwinter in the soil. They begin feeding as soon as their host crop comes out of dormancy and starts to grow. Army cutworms are brownish-black without any distinguishing markings and will be found in the soil around the crowns of the plants during the daytime. They feed on the foliage above the surface of the ground at night. (Figure 3). After completing development the adult moths fly to the Rocky Mountains before returning to complete the cycle.

Treatment threshold

In established alfalfa fields, stand loss is rarely observed, but the delay in green-up may reduce yields of the first cutting if cutworms are numerous. Consider treatment in established fields when four or more cutworms per square foot are found. In fields less than a year old, food reserves in the roots are limited and feeding may be enough to kill individual plants and produce stand loss. Treatment should be considered if two or more cutworms are found per square foot in newly seeded alfalfa.

New generic insecticides