Development and Behavior of Black Cutworm (Lepidoptera: Noctuidae) Populations Before and After Corn Emergence

Field studies show that, if tillage operations occur 2 days before planting or on planting day and herbicide applications occur 2 days before planting, on planting day, or 2 days after planting, black cutworm, Agrotis ipsilon (Hufnagel), larvae present at the time of tillage or herbicide application can survive and produce significant damage to seedling corn. The number of herbicide- or tillage-killed plants per square meter did not seem to affect the survival of black cutworm unless the plant mortality occurred 8 or 14 days before corn planting (15 or 21 days before corn emergence). Black cutworm that presumably fed only on surface plant debris for 11 days survived and significantly affected the corn crop. On the basis of accumulated centigrade degree-days necessary for black cutworm to shift to subsequent stadia, survivors feeding on plant debris will develop as quickly as survivors feeding on weed seedlings, and both populations can achieve cutting stadia (fourth to sixth) by the time corn emerges.