Kansas Fall Pests on the Rise as Armyworms Multiply and Cutworms Arrive

Fall armyworms have been arriving in Kansas since mid-June and their numbers continue to rise, according to pheromone trap counts statewide. In September, the traps caught a total of 12,000 fall armyworms (Figure 1). Another potential fall pest, army cutworms, have also been detected in western Kansas since early September.

Army cutworms are late-fall and early-spring pests that target several Kansas crops, including alfalfa, wheat, and triticale. These moths migrate into Kansas from the Rocky Mountains in the fall. Trap counts of 800 or more army cutworm moths in an area through October may indicate significant caterpillar activity the following spring.

Northwest Kansas has seen the highest number of moths being trapped weekly, with female moths laying up to 1,000 eggs. After hatching, caterpillars will feed until cold weather forces them below ground. They will complete their growth next spring and then burrow into the soil to pupate.