Although the individual Insects are wingless and cannot fly, snailcase bagworms attach to many surfaces and can easily be transported to new sites. The developing Insects feed on a wide variety of plants but rarely cause significant plant injury. Instead, problems occur as the full-grown larvae migrate to sites to pupate. During this time, large numbers may firmly attach themselves to sides of buildings, fences, mailboxes and other surfaces, creating a nuisance. The caterpillars are greenish or reddish-gray with a black head.
Adults are wingless and nearly legless moths.
Only females are known to occur in Colorado. Snailcase bagworms survive winter as young caterpillars protected within the case of the mother insect. They become active in midspring and feed on the leaves of a wide variety of native and cultivated plants, including sagebrush, saltbush, rabbitbrush, willow, mountain-mahogany, various fruit trees, squash, povertyweed and other wild crucifers, and alfalfa. The feeding injuries appear as small areas progressively gouged out of the leaf surface. Serious plant injury is rare.