Black Cutworm: April - June
Black cutworm has a large range of hosts, but in the Midwest it is a major pest in corn production.
Unlike other cutworms, black cutworm (Agrotis ipsilon [Hufnagel]) does not survive the winter and moths migrate to the Midwest from southern states each spring. A single mated female can lay 1,300 eggs, which are generally laid in crop stubble, low spots in a field, and in weedy areas. It is difficult to predict when and where black cutworm will occur, so it is essential to monitor their arrival by using pheromone traps.
Corn is most susceptible to black cutworm damage from V1 to V4 (one leaf to four leaf stage). Young larvae, generally less than ¾ inch long, will feed on leaf tissue, which sometimes results in a windowpane effect on new leaves. Older larvae, generally greater than ¾ inch long, can cut corn seedlings above or below the soil surface, depending on soil conditions. Cutting rarely occurs once plants reach V5.
Management practices include insecticides or Bt corn hybrids, though Bt is less effective when high levels of larvae are present. Weed control and tillage in the spring may reduce the attractiveness of that field for egg-laying.