Siberian moth

Dendrolimus sibiricus Chetverikov

Synonym(s): Siberian silk moth, Larch moth, Siberian conifer silk moth, larch caterpillar

Siberian moth is a major pest of conifers and is native to Northern Asia. It is not yet known to be in North America. Eggs and larvae may be especially problematic as hitchhikers in packing material, although any life stage can be found in plant material. Development usually lasts 2 years but it may vary from 1 to 3 years depending on temperature. Adults fly from the end of May to the middle of July. Immediately after mating, females lay eggs on the needles, mainly in the lower crown, but also on the ground. Newly laid eggs are light-green, but soon become creamy white and then darker and spotted. Eggs have a 13-15 day development period. The black to dark-brown caterpillar has numerous spots and long hairs. The 2nd and 3rd segments crossed by blue-black stripes. Larvae feed until late autumn and spend the first winter in forest litter. In spring, after snow melt, caterpillars climb up to the crown and feed for the entire summer before returning to the forest litter for their second winter. In spring they begin to feed intensively and pupate in May-June in cocoons made from crude web. Cocoons can be found in crowns, on branches, or stems. The pupa is brown and 1 1/4 inches long. Adult wingspan ranges from 1 1/2 to 3 inches with a body length of 1 1/4 inches. The color of moths varies from light yellowish-brown or light grey to dark brown to almost black. Front wings are distinctively marked with two characteristic crossing dark stripes and a white spot in the center.

Identification, Biology, Control and Management Resources

Exotic Forest Pest Information System For North America - North American Forest Commission