–by Anthony Zukoff – Entomology Southwest Research and Extension Center
Garden City, KS
Noticeable numbers of army cutworm moths, also called Miller moths, have been observed in a couple locations in western Kansas this year. Army cutworms are late fall and early spring pests of several Kansas crops, especially wheat. These moths begin migrating into Kansas and neighboring states in the fall from their over-summering locations in the Rocky Mountains. This year, moths began showing up in western Kansas during the first week of September. In the last six weeks, over 1600 moths have been collected in pheromone traps at a location in Finney County. Trap counts of 800 or more moths in an area may indicate increased caterpillar activity the following spring. Right now, females will be laying eggs on the soil surface of freshly cultivated, weedy or newly seeded winter wheat fields. Each female can lay up to 1000 eggs or more. After hatching, caterpillars will begin feeding and do so until cold weather forces them below ground. However, it is possible for them to resume feeding on warmer winter days. Caterpillars will complete their growth next spring and then burrow into the soil to pupate. Sexually immature adults emerge in late spring and migrate back to the mountains for summer. Fields should be scouted during warm periods between February and April. Fields under stressful conditions, such as the current drought, may suffer economic damage with only 1-2 caterpillars per square foot. Typically, treatment will not be necessary until populations average 4-5 per square foot and well-tillered fields under good growing conditions can tolerate up to 10 per square foot without measurable yield loss. More information regarding control options for this pest in wheat and other crops can be found in the KSRE Insect Management Guides.
Army cutworm moths in a pheromone trap in Finney County