Cutworms and armyworms

Cutworms and armyworms are soil-dwelling and foliage-feeding caterpillars that damage a wide range of plants in Western Washington landscapes. You will see jagged, irregular holes in leaves and sometimes seedlings cut at soil level. Armyworms occasionally appear in aggregations and can skeletonize foliage quickly. Many feed at night and hide in soil litter during the day. Damage appears spring through fall depending on species and generation.

Handpick caterpillars at night using a flashlight, checking soil and base of plants. Create barriers around seedlings with cardboard collars that extend both above and below soil. Clear dead leaves and dense mulch where caterpillars hide during the day. Bacillus thuringiensis (Bt) applied to foliage targets young larvae before they bore into buds. Maintain clean cultivation around plants to remove hiding places. Most populations self-regulate through natural enemies; severe outbreaks are uncommon in home gardens.