Gray Bud Weevil (Sciaphobus Squalidus)

Pest Type: Fruit Pest

Row: Coleoptera – Coleoptera

Family: Weevils – Curculionidae

Numerous in woodland and forest-steppe, in the steppe zone, is found in stations with increased moisture. It damages all fruit, berry crops, grapes, and forest species.

Beetle 5-7 mm long, covered with gray scales; elytra ovate; the rostrum is shortened, legs and antennae are yellow-brown, the club of the antennae is dark, eyes are large; webbed wings are not developed. The beetle does not fly. The egg is 0.8 mm in size, oval; milky white. Larva -5-6 mm, white, with a light brown head, rows of setae and spines on the body; larvae of the first age on the ventral side of the thoracic segments have three pairs of long setae intended for movement in the soil. Pupa 5-6 mm long, white.

Immature beetles and larvae in the soil over winter. Beetles emerge at an average daily temperature of 10 ° C at the beginning of the swelling and budding of the kidneys. The rise in the crown of trees and feed for 20-30 days only in the afternoon. At night, they descend to the ground and hide in various shelters. In mid-May, after fertilization, the females begin to lay eggs. Eggs are laid in groups of 10-40 pieces under the edge of the top of the sheet. Egg-laying lasts 8-11 days. Fertility – 200-300 eggs. The larvae regenerated after 12-16 days fall to the ground and penetrate the soil to a depth of 40-60 cm, where they feed on small roots of trees without causing significant harm.

After hibernation, the larvae continue to develop until the end of next summer and in August pupate in a small box at a depth of 40-60 cm. The beetles formed in September remain in the earthen small box until spring. At the same time as the bugs, the larvae of the first-year winter. Thus, the development of gray kidney weevil lasts two years. The main harm is caused by beetles, eating buds, buds, and leaves. The buds are eaten completely or gnaw out holes in them, pestles and stamens gnaw out in the buds, leaves are eaten from the edges.

The laid eggs of the gray kidney weevil infect the egg-eaters; larvae are braconids. A significant number of larvae die during their penetration into the soil from ground beetles, earwigs, spiders, and other predatory arthropods.

Protective measures. With a population exceeding 20-30 beetles per tree, during the period of budding, it is necessary to spray the trees with insecticides.

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