This pictorial describes how western spruce budworm larvae feed on young western larch and the trees' responses to this damage. Larvae feed not only on the current year's foliage-their usual diet on most coniferous hosts-but also sever stems of current year's shoots. Multiple-topped, bushlike trees develop in direct response to the amount and type of damage. As a result, trees cannot maintain straight boles and good form. Sustained budworm damage could conceivably influence the management of western larch-one of the more important conifers in the northern Rockies.