When is the optimal time to treat for fall armyworm in corn?

The optimal time to treat for fall armyworm in corn is when 75 percent of the plants show leaf feeding. This timing is critical because it indicates that the infestation has reached a level where the larvae are actively feeding on the foliage, which can significantly impact the health and yield of the corn plants. Treating at this stage allows for effective management of the pest population before they can cause extensive damage.

Waiting until larvae are over 1 inch in size would mean that the pests have already had adequate time to feed and potentially cause significant injury to the crop. Treating immediately after egg hatch may not be effective because the tiny caterpillars might not be concentrated enough to warrant intervention or may not yet have started causing noticeable damage. Lastly, treating when the plants are flowering is generally too late, as the critical growth stages for corn which greatly affect yield occur before flowering, making early intervention essential for successful pest management.