Spruce budworm

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Damage caused by the Spruce budworm

Larval stages of spruce budworms cause damage to red spruce, black spruce and other conifers. Larvae generally feed on new buds and needles of spruce trees. These larvae also bore into buds and feed on their tissues. Damaged needles turn reddish-brown. In case of severe infestation, larvae of spruce budworms can cause reddish-brown hue in the tips of branches and treetops. Spruce budworms can completely defoliate trees and eventually kill the trees.

Facts (show all)

+Common names

Spruce budworm

+Scientific name

Choristoneura fumiferana, Choristineura orae

+Identification

Adults: Moths of spruce budworms are gray to orange- brown in color.

Eggs: Eggs are of spruce budworm are greenish in color, oval in shape and 0.5 mm long.

Larvae/Caterpillars: Mature larvae of spruce budworm are reddish- brown in color with large ivory- colored areas and dark brown colored head capsule.

Pupae: Pupae of spruce budworm are reddish-brown in color.

+Biology

Adults of spruce budworm generally emerge from pupae in late July through early August. After mating, females generally lay eggs in masss on the lower surface of needles. Eggs hatch within 10 days into small larvae. These larvae then live under bark scales (protected areas) where they spin silken tents in which they remain inactive throughout the winter and spring. These larvae then become active in early May through late June and tunnel into needles and new bud growth. Feeding continues until they become mature in late July. Mature larvae then pupate in silken cocoons on the tree foliage. Adult moths emerge from pupae within 10 days and life cycle continues. Under favourable conditions, spruce budworms can complete 1 generation in a year.

+ Organic Control of the Spruce budworm