Siberian Moth

(Dendrolimus sibiricus), a butterfly of the family Lasiocampidae, a dangerous pest of coniferous forests. The wingspread reaches 90 mm, and the coloration is gray. The Siberian moth is distributed from the Pacific coast in the east to the Southern Urals in the west and from Vakutia in the north to North China in the south. It primarily damages larch, fir, and cedar trees; less frequently, it attacks spruces and pines. The moths first appear at the end of June; mass flight usually begins in mid-July and ends in early August. The Siberian moth has a two-year or one-year generation. In a two-year generation the number of larval instars is seven or eight; in a one-year generation, five or six.

Most of the caterpillars winter on the forest floor in the third instar. Wintering in larch plantings occurs mostly in the second instar. After thawing of the snow cover, the insects feed on conifer needles, devouring them completely. Sometimes they damage buds and even young cones. Their total destruction of the needles is one of the causes of mass reproduction of tree-trunk pests, especially cerambycids, which damage plantings extensively. The Siberian moth is controlled by the fly Telenomus, a widespread natural enemy. Mass destruction of the moth usually occurs as a result of epizootics caused by bacteria.

The most effective control method is the aerial dusting of foci of Siberian moth during the development of caterpillars of the youngest instars.