Western Spruce Budworm Description

The Western Spruce Budworm (Choristoneura occidentalis) is a vital local defoliator of Douglas`firs, true firs and spruce trees. This native defoliator occurs throughout most of western North America. Budworm infestation could last for as high as 8 years and even more
Both male and female moths have a similar appearance, with the females being a little more robust when compared to the males. A full-grown moth has a length of about 12.7mm and a wingspread of between 22mm to 28 mm. Both the male and female moths fly. The orange-brown or gray forewings are streaked or banded, with white dots on the margin of the wings. They lay oval-shaped eggs; light-greened color, with an average length of 1.2 mm and shingles-like overlap.
A larva has six developmental stages. When larvae are newly hatched, they are usually yellow-greenish and with brown heads. Within the next three stages, the color changes from brown heads to black heads and collars with cinnamon-brown and orange bodies. In their fifth stage of development, larvae’s head color changes to reddish-brown with black triangular markings, black collars, and olive-brown bodies with little whitish markings. A more developed larva has a length of about 25 to 32 mm with light chestnut-brown or tan heads and collars, while the bodies are reddish- or olive-brown.
A pupa has a broad head end while the tail is narrow. At first, they are brownish-green or brownish yellow but later turns reddish-brown.

Larvae feeds on buds and new shoots of host trees. This causes discoloration of the foliage from the tops of the trees downwards. Larvae partially feeds on the needles which makes them to dry out and turn red-brown. Continual defoliation for several years can cause complete defoliation of an infested tree.

If your Douglas-firs, spruces are infested with Western spruce budworm, give SprayTech a call at 720.248.0000 for a free estimate.