Yellowstriped Armyworm
Spodoptera ornithogalli (Guenee), Noctuidae, LEPIDOPTERA


DESCRIPTION

Adult - The yellowstriped armyworm moth has dark forewings with white and brown markings and white hind wings. The wingspan ranges from 32 to 38 mm.

Egg - Approximately 0.5 mm and 0.4 mm in diameter, the ribbed, greenish egg gradually becomes pale pink or brown before hatching. The egg mass is covered with scales from the moth's body.

Larva - This smooth-skinned, pale gray to jet black caterpillar has a yellowish-orange stripe along each side and a pair of black triangular spots on the top of most segments. Its head capsule is brown with black markings and a white inverted "V." The sixth larval instar may be as long as 45 mm.

Pupa - The brownish pupa is about 18 mm long and 5.5 mm wide.


BIOLOGY

Distribution - The yellowstriped armyworm occurs from New York southward into Mexico, westward to the Rocky Mountains, and in some areas of California and the West Indies. In this country, however, it is most common and most injurious in the southern states. In North Carolina, this caterpillar is observed annually in field and vegetable crops.

Host Plants - The yellowstriped armyworm is a general feeder. Some of its hosts include alfalfa, asparagus, bean, beet, cabbage, clover, corn, cotton, cucumber, grape, grass, jimsonweed, morning glory, onion, pea, peach, peanut, sweet potato, tobacco, tomato, turnip, wheat, watermelon, and wild onion.

Damage - This foliage-feeding caterpillar is sporadically injurious to young crop stands. Defoliation at this stage can be a problem.

Life History - Yellowstriped armyworms overwinter as pupae in the soil. In southern states, moth emergence begins in early April and continues into May. After mating, females deposit egg masses on foliage, trees, or buildings. Approximately 6 days later, the eggs hatch and the larvae begin feeding. Although these caterpillars emerge by late spring in the South, they may not appear before July in northern and midwestern states. Larvae feed during the day on tender foliage over a 3-week period. Mature 6th instars burrow into the soil and change into pupae. Two weeks later, the second generation of moths emerges. In southern states, including North Carolina, 3 to 4 generations occur each year.


CONTROL

Yellowstriped armyworms seldom require control in North Carolina. Since large larvae are difficult to control with insecticides, early detection is important in maintaining populations below economic injury levels. For chemical control recommendations, see the current North Carolina Agricultural Chemicals Manual.

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