Black cutworm

Agrotis ypsilon

Разред Lepidoptera, Сем. Noctuidae

Hosts

The Agrotis ypsilon is widely distributed and often among the most damaging species in Bulgaria. It thrives in moist areas with high groundwater levels, often along riverbanks. The pest attacks a variety of crops, including sugar beet, fodder beet, lettuce beet, sunflower, cotton, potatoes, peanuts, clover, soybeans, peas, beans, cucumbers, watermelons, melons, cabbage, and onions. Among weeds, it infests Chenopodium (loboda), Convolvulus arvensis (bindweed), Cirsium arvense (creeping thistle), Amaranthus (pigweed), and others.

Life Cycle

The Ypsilon dart moth produces two to three generations annually. It overwinters as a fully developed larva or pupa in the soil.

Egg Laying

Females lay eggs scattered or in clusters of 10–15 to 200–250, mainly on the underside of leaves near the soil surface and directly on the soil itself. Average fecundity is approximately 1,500 eggs. Embryonic development takes 3–4 days at 25–30°C but slows significantly at lower temperatures.

Newly hatched larvae initially feed on weeds before migrating to cultivated crops. The damage they cause resembles that of the winter cutworm (Agrotis segetum). Larvae have five instars, with the last three being the most harmful. Feeding during spring lasts 45–60 days, while summer generations complete feeding within 14–21 days.

After completing their development, larvae pupate in the soil (within an earthen chamber) at a depth of 5–6 cm near the feeding site. The pupal stage lasts 11–17 days, depending on the temperature. Moths from the second generation emerge in July–August, while those from the third generation fly in August–September.

One generation of the Ypsilon dart moth (from egg to adult) completes its cycle within 35–60 days, depending on temperature and host plants.

Larva

The larva is earthy gray to gray-brown with a lighter longitudinal stripe on its back. Fully grown larvae reach a body length of 45–55 mm.

Pupa

Pupae are dark brown and measure 19–25 mm in length.

This pest is highly destructive to a wide range of crops, particularly during its larval stages, making timely monitoring and control measures critical.