BLACK CUTWORM: Agrotis ipsilon, Noctuidae

ADULT: Wing span of these moderate sized moths range from 1 5/8 to 2 1/8 in. Fore wings of male are clay colored and shaded with darker reddish-brown to black in basal two-thirds. Female fore wings are darker in basal two-thirds and sometimes paler at base. In both sexes the kidney-shaped (reniform) spot is a dark crescent-shaped ring with a dark line emanating outward and hind wings are whitish to gray with dark scales on veins. The claviform spot (proximal to and beneath reniform spot) is an elongate oval, and the orbicular spot (proximal to reniform spot) is small and round to tear-shaped.  Moths begin depositing eggs 7 to 10 d after emergence.

EGG: The whitish (becoming variegated brown with age), spherical shaped eggs have ribs radiating from top. Eggs are deposited singly or in groups of up to 30. Larvae emerge in 3 to 6 d.

LARVA: Color ranges from light gray to black on top and lighter below. Two lighter stripes running down the center of the back are visible on lighter specimens, but all larvae lack an obvious band down their back. Two rows of small, black, raised bumps (tubercles) run down the back; two per segment. Cuticle is covered with large and small granules. Their head is brownish with many dark spots.  Sutures on front of head form an inverted "V". Larvae have 3 pairs of true legs and five pairs of prolegs.  Larvae complete development in 20 to 40 d.

PUPA: Brown pupae 3/4 to 7/8 in. long are found in the soil. Adults emerge in 12 to 20 d.

GENERATION TIME: 35 to 66 d.

DAMAGE: The black cutworm is a pest throughout the state and is a serious pest of many vegetables in southern Florida. Most of the feeding occurs at ground level. Larvae feed on young plants, cutting off leaves, or in later instars, entire plants. Populations of this pest tend to be higher in weedy and in wet fields.

CONTROL: Parasitic flies and wasps can exact a great deal of control on black cutworms. These natural enemies, as well as predacious ground beetles, can exert tremendous control pressure that may approach 80%.  However, seedlings emerging in fields without resident natural enemy populations can experience significant stand loss from first generation cutworms.  Adult populations can be monitored with black light and pheromone traps. Seedling corn should be scouted as frequently as twice per week to detect cutworms or their damage, particularly in areas known for this pest.  Young larvae are more easily spotted on foliage, while late instar larvae burrow in the soil.  Pesticides are available for at-plant, pre- and post-emergence broadcast and banded applications. Formulations, rates, and pre-harvest intervals of insecticides for black cutworm control are listed below for sweet corn (Table 1) and field corn (Table 2).