Cutworm Scouting

When everything looks great from a distance, don’t forget to get out of the pickup and check your sunflower fields for cutworms this time of year.  Sunflowers can have irreversible damage in the seedling stage from several species of cutworms. Damage is caused by cutting off the seedling, sometimes below the cotyledon or before they even emerge out of the ground. As the plant matures, damage moves to the leaves and the plant is typically able to recover (V4-V6 stage).

Damage can first be noticed by bare patches in a field or several missing plants in a row. Generally, cutworms can be first be found on south facing slopes (warmer), areas that border grass/pasture or a spot in the field that had weed issues the year before.  Scouting towards evening can be helpful, otherwise look underneath the soil surface or stubble during the day. If there is a row of plants missing start by looking for the larvae near the next undamaged plant.

Economic threshold is when you have a 25-30% stand reduction or when there is 1 small larvae per sq ft (1 inch or smaller). Several insecticides work well and spraying towards nightfall is best.