Fight with the cabbage scoop
Latin name: Mamestra brassicae
Russian name: Sovka kapustnaya
Type of pest: Omnivorous pests
Series: lepidoptera - Lepidoptera
Family: scoops — Noctuidae
Happens everywhere. In addition to cabbage plants, it damages field, vegetable, fruit and forest crops belonging to 30 families.
A butterfly with a wingspan of 40-50 mm; front wings are dark brown with a yellowish-white wavy line, which in the middle of the wing forms two teeth facing outwards in the form of the Latin letter "W"; two dark spots are located near the front edge, the kidney-shaped spot is bordered with white or is partially white itself; hind wings are gray, darker at the edges. The egg is 0.6–0.7 mm in size, yellowish-white, hemispherical, with 32–38 radial ribs, of which 12–14 reach the micropylar zone.
The caterpillar is 35-50 mm long, 16-legged, variable in color, from grayish-green to dark brown, almost black, on the sides of the body there is a wide yellow stripe, on the back there is a dark pattern in the form of a "herringbone tree". The pupa is 19-24 mm in size, reddish-brown, with two long outgrowths on the cremaster that end in a flattened mace.
Pupae overwinter in the soil, at a depth of 8-12 cm. Butterflies fly out in May. The beginning of the flight of butterflies coincides in time with the establishment of the average daily air temperature of 14-16 °С and the sum of effective soil temperatures at a depth of 7 cm of 189-196 °С. Butterflies additionally feed on the nectar of flowers, most often weeds. They fly in the evening and at night, and during the day they hide in secluded places. The duration of the flight of butterflies is 30-45 days, mass flight is observed for 20-25 days. The female lays eggs in groups of 20-80 pieces on the underside of the leaves of various cultivated plants and weeds, mostly cabbage. Fertility — from 600 to 2600 eggs. High temperatures and low air humidity during the flight period of butterflies limit their fertility. Embryonic development lasts 6-12 days.
Caterpillars live in groups until the second age, skeletonize leaves from below, without affecting the epidermis of the upper side. Starting from the third age, they crawl over the plant and gnaw irregularly shaped holes in the leaves. They feed intensively at night and at dawn, and in the daytime there is a decline in mobility and feeding activity. Caterpillars of middle and older ages often bite into the cob, in which they make moves and contaminate it with their liquid excrement. In cauliflower, caterpillars damage both flowers and inflorescences. The development of caterpillars lasts for 25-30 days. For pupation, they migrate into the soil to a depth of 5-12 cm.
Some of the pupae of the pest enter diapause in case of insufficient soil moisture. A total of effective temperatures of about 700 °C is required for the complete development cycle of the cabbage scoop. The flight of butterflies of the second generation takes place in the second half of July - in August. Caterpillars of the second generation develop for 30-40 days and damage cabbage of medium and late varieties. Caterpillars pupate at the end of September.
About 39 species of entomophages limit the number of pests. Eggs are infected by Trichogramma evanescens Westw.
Protection measures. Snow plowing. Cultivation between rows during the period of mass pupation of the first generation. Destruction of flowering weeds during additional feeding of butterflies. Two releases of the trichogram of 100-150 thousand individuals per hectare against each generation of the pest — at the beginning of egg laying and 6-7 days after the first release. The use of biologics or insecticides is advisable when the scoop populates 5% of plants with an average density of two or more caterpillars per plant.