Silkworm Pine (Dendrolimus Pini)

Pest Type: Soft Pests

Row: Lepidoptera – Lepidoptera

Family: Cocoon Spiders – Lasiocampidae

It is found everywhere. Damages ordinary pine, in rare cases, other conifers.

A butterfly with a wingspan of 60-80 mm, the color of the front wings is yellow-brown to gray-brown, on each wing there are three transverse wavy lines and to the middle of the wing there is a small lunate white spot; in a calm state, the wings are folded in the form of a roof; hind wings gray, one-color. An egg up to 2 mm in diameter, first greenish, later dark. Caterpillar of the last age 90-100 mm long, gray-brown, with rare reddish hairs, dark blue spots on the dorsal side of the second and third segments; along the back stretches a series of rhombic spots with a bright middle. Pupa 20-40 mm long, dark brown, in a cocoon.

Caterpillars of the third and fourth centuries hibernate in forest litter, most often near a tree trunk, individual individuals pass shallow into the soil. In spring, at a temperature of 10 ° C, caterpillars crawl along the trunks into the crown at the place where they lie and begin to feed on young needles, and shoots and buds of May are also damaged. Eat-in the twilight and predawn hours. Over the entire development period, one caterpillar eats 20-35 g of needles, with 2-3 g in the fall and 18-32 g in the spring. Caterpillars of the male pass 6, caterpillars of the female – 7 centuries. In the first half of June, pupate among pine needles on branches or on tree trunks. After 20-25 days, butterflies come out. Their years last until mid-July.

After fertilization, females lay eggs on needles in groups of 20-150 pieces. Fertility – an average of 300 eggs. After 14-20 days, the caterpillars that feed on the needles of this year revive, gnawing the needles on the sides in the apical part. Caterpillars of the second age nibble needles along the entire length. In October, the caterpillars go to winter. Annual generation.

A combination of needles causes weakening of trees, drying of branches and their settlement with bark beetles, barbel.

The number of pine silkworms is reduced by more than 60 species of parasites and predators. The laid eggs infect the ovids, caterpillars, and pupae – the braconids; ichneumonids and others. Caterpillars and pupae feed on ants from the genus Formica and birds – cuckoo, oriole, jay.

In wet weather, epizootics are observed due to infection with fungal, bacterial and viral diseases.

Protective measures. Attraction to plantations and protection of insectivorous birds. With a population exceeding 400-500 caterpillars per tree, treatment in the early spring with biological products or insecticides of the forest litter and the butt of the trees.

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