Gamma Moth

(Autographa gamma), a moth of the family Noctuidae, a dangerous polyphagous pest. The wingspread is 36–48 mm. The fore wings are gray, brown, or reddish cinnamon with dark lines, wavy stripes, and diffuse spots; in the middle there is a silvery white or yellowish spot in the form of the Greek letter gamma. The hind wings are grayish yellow and have a brown hind margin.

The gamma moth is distributed in Europe and Asia. It damages flax, hemp, many legumes, sugar beets, and other crops, causing the greatest harm in years of mass reproduction. The larvae eat leaves and gnaw through buds, flowers, ovaries, and underripe fruits. The gamma moth yields one generation in the north and four generations in the south. The first-generation moths appear sometime between early June and early July. The females produce about 500 eggs, which hatch three to seven days after they are laid. The caterpillars feed initially on the leaves of weeds and later on cultivated crops. In the summer the caterpillars, having finished feeding, pupate in fragile silky cocoons on plants or, less frequently, in the top layers of soil. In the autumn pupation occurs in the soil. Both the moths and the caterpillars are capable of migrating long distances. Periods of intensive reproduction occur every four to ten years.

Control measures include weeding, interrow tilling, and deep autumn plowing. The last two procedures destroy a substantial number of caterpillars and pupae. Also effective is the use of insecticides to kill the caterpillars.