Western Spruce Budworm – Choristoneura occidentalis

Western Spruce Budworm – Choristoneura occidentalis Scientific name: Choristoneura occidentalis Common name: Western spruce budworm   Appearance: Western spruce budworm is a small moth ranging in size from 12.7 mm with a wingspread of 22 to 28 mm. It has an orangish-brown forewing with streaking and white dots on the margins of the wings. Both males and females have similar morphology. The larvae are initially yellowish-green with a brown head but later turn olive with light chestnut heads.   Host plants or food: Western spruce budworm commonly feeds on conifers, mainly Douglas fir, white spruce, Engelmann spruce, grand fir, and subalpine trees.   Territory: Throughout North America   Mode of damage: Western spruce budworms are leaf chewers and defoliate the conifer trees. However, they may also feed on cones and flowers.   Habits and life history   Western spruce budworms lay eggs on the lower side of the conifer needles, approximately 150 in number. Ten days later, the eggs hatch into larvae, which spin silk tents in which they overwinter. After they come out of hibernation, they feed and turn into pupae. The larvae feed on new foliage, and after complete defoliation, they move to older ones. The adults start emerging in July, after which they mate, lay eggs, and die right after. It takes a year to complete one lifecycle.