Symptoms, description and lifecycle

External feeding on leaves, stalks and stems results in falling leaves, small holes in the stems or cut stems. External feeding on tubers and roots results in a variety of holes, ranging from those that are small and superficial to very large deep ones. Whole plants (e.g. lettuces, leeks, maize, cotton or small spruce seedlings) fall over, and on root crops (e.g. beetroots) deep holes become visible at and above the soil surface. Damage to underground tubers (e.g. potatoes) may be difficult to recognise before harvest.

Adult: 40 mm wingspan; dark brown forewings with, in the middle, a uniform spot and a clearer, circular spot. The hind wings are white in the male and grey in the female. The periphery of the wings bears a thin black border. Adults can lay 800-1200 eggs.

Larva: 45-50 mm, reddish head, greyish body with two parallel longitudinal lines in the middle region. On each segment, two small black spots at the front and two at the back, each bearing a small bristle.

Caterpillars are voracious, they feed at night, gnawing the foliage and cutting the petioles. During the day, they hide by rolling up under a lump of earth or at a shallow depth in the ground.

Organism

Agrotis segetum

Conditions favouring pest

Turnip moth requires shelter and dry conditions to allow for increased activity and development. Larvae struggle to survive in low temperatures.

Host range

Attacks cultivated plants belonging to more than 15 families. Host plants include wild plants, couch grass (Agropyrum spp.), bindweed (Convolvuluv spp.), plaintain (Plantago spp.) vegetables including Brassicas (cabbage, cauliflower), Solenaceae (capsicum, tomatoes, potatoes), cereals, tobacco and grape vines.

Method of spread

Adult moths are strong fliers and can fly over large distances.

Confused with?

There are several noctuid moths native to Australia some of which look similar to Turnip moth. These include the brown cutworm or pink cutworm, (Agrotis munda) and; the bogong moth, (Agrotis infusa).

Where?

Europe, Africa, Northern Asia, including China.