Rich Pope, ISU Extension program specialist coordinates a network of traps in more than 75 Iowa counties to monitor when black cutworms arrive and potentially lay eggs. Trap capture information is valuable because it allows scientists to predict when crop damage may occur. The trap capture data do not indicate where the females lay their eggs, how many eggs they lay, what the cutting potential is, or even whether moths stay within the area where they were trapped. Moths may depart the next night and continue their migration northward to Minnesota or eastward to Illinois. Trap captures alone do not mean the females have laid eggs in a field.
Rice suggests an integrated pest management strategy for control of black cutworms.
Delaying treatment until a black cutworm problem develops in the field makes economic sense. Companies may guarantee preemergence-applied insecticides for black cutworm control. Insecticide performance guarantees should not lull farmers into a false sense of security. Just because the field was sprayed early in the season does not preclude the possibility of crop injury by insects later in the season. In addition, the scouting-based treatment may do double duty in controlling corn flea beetles, a secondary benefit missing from the early treatment strategy.