Scientific Name: Pseudaletia unipuncta (Haworth)
Order: Lepidoptera
Development: Holometabola
Life Stages
Egg: The minute egg is greenish-white and globular.
Larva: The young larva is pale green. The full-grown larva, 30 to 35 mm long, has a yellow to brownish-green body with three dark, longitudinal stripes.
Pupa: The pupa, reddish-brown at first, gradually darkens until it is almost black.
Adult: The adult moth is pale brown to grayish-brown with a wingspan of about 38 mm. There is a characteristic white spot in the center of each forewing.
Host Plants
The armyworm infests all grass crops, especially corn, millet, bluegrass, crabgrass, fall panicum, and small grains. Under stress of hunger it will eat some broadleaved plants.
Damage
Armyworms, apparently native to North America, vary greatly in abundance and destructiveness from year to year. They are most destructive to small grains when wet weather has caused lush growth in the fields. Armyworms eat succulent leaves first. As the foliage is consumed, they move to other parts of the plant. In headed small grains, the caterpillars may feed on awns and tender kernels, frequently cutting through the stem immediately below the head. Farmers often notice both snipped off heads and leaf feeding. In North Carolina, damage to small grains occurs most commonly in the eastern coastal plain.
Life History
Armyworms overwinter as partly grown larvae. Early in the spring they resume feeding on lush stands of grass and small grains. The larvae hide during the day and feed at night. As small grains mature, the larvae often migrate en masse (“armies”) from adjacent crops into fields of corn or other late-season grass crops.
First generation adults appear and mate in May or June. After feeding on sweet substances for 7 to 10 days, the females lay eggs at night on succulent grasses and grain crops. An individual female may deposit as many as 2,000 eggs (in clusters of 25 to 134). Six to ten days later, second generation larvae emerge and feed for about 3 weeks. They then drop to the ground and pupate in earthen cells 5 to 7.5 cm deep in the soil. Moths emerge about 4 weeks later. There are five or more generations per year in North Carolina, however, generations that develop after early July are usually not an economic threat due to the natural controls.
