Adults
Spongy moth (Lymantria dispar) is a highly destructive invasive species. First introduced to the United States over 150 years ago, it is now permanently established in more than 20 eastern states and some eastern Canadian provinces.
Egg masses
Spongy moths start as eggs that are laid in masses that have a “spongy” appearance. These egg masses are laid in the summer on trees, shrubs, or any outdoor surface. The eggs overwinter and hatch in the spring when trees are leafing out with fresh, tender new growth.
Catepillars
When they emerge, the caterpillars are very small – about a quarter of an inch. But they are very hungry eaters and quickly grow up to three inches long within a few weeks. As they mature, they develop five pairs of blue dots followed by six pairs of red dots on their backs. It is only the caterpillars that eat and damage trees and shrubs.
Pupae
After eating their fill of trees and shrubs, the caterpillars pupate. The pupa is generally a dark brown color. They can usually be found attached to tree trunks, buried in leaf litter, or attached to almost any outdoor surface. Pupation lasts approximately 1-2 weeks.
Male Moths
Male moths are about an inch long and tan/brown in color with wavy lines and a distinct “dot and comma” marking on each wing. They have large, feathery antennae that they use to detect the scent of females from up to a mile away.
Female moths
Female moths are larger than the male moth and are a cream color with dark brown wavy lines and a distinct “dot and comma” marking on each wing. Most female spongy moths detected in Washington cannot fly. They can lay up to 1,000 eggs, which means that spongy moth populations can explode rapidly if they are allowed to establish in an area.
Fall webworm (summer/fall)
Tent caterpillars (Western and Pacific) (seen in spring)