Silverspotted tiger moth

Clusters of brown, black, and yellow hairy caterpillars (just under 4cm long) hibernate on conifer twigs and become active on warm winter days. The caterpillars feed on needles, often creating dirty-looking webs that tent branches; feeding occurs mostly in fall and winter with webs most noticeable in spring. Douglas-fir is the preferred host, but pine, spruce, true firs, and arborvitae are also attacked.

Minor infestations cause little harm. These defoliators rarely occur in high numbers requiring control. Urticating hairs on larvae can cause skin irritation; wear gloves when handling. Prune webbed branches in spring if objectionable. Accept moderate needle loss on healthy conifers.