Western Spruce Budworm Larvae

Birth

• The adult moths start mating as soon as they mature. Each female lays about 150 eggs on conifer needle undersides within seven to 10 days of mating. It takes about 10 days for the larvae to hatch from the eggs.

Hibernation

• The new larvae immediately seek protected spots in the crevices of the bark or within the needles. The pests do not feed at this point. Once they find a suitable spot, they spin tentlike shelters referred to as hibernaculae. The larvae remain dormant within these shelters throughout the winter and most of spring.

Emergence and Damage

• The hungry larvae emerge in early May and start seeking food. Early food sources include the needles from the past year, closed buds and the new reproductive buds. The pests create tunnels as they eat into these areas, leaving traces of excrement and silk webbing at the entrance points. The larvae then move to the new foliage, their preferred food, and spin webs around the leaves. This leads to discoloration of needles and twisted and stunted new growth. The larvae eat and destroy new foliage.

Pupal Stage

• As they feed on foliage, the larvae grow rapidly and reach maturity in about 40 days after emerging from hibernation. The brown headed, mature larvae have two distinct pair of white spots on their olive brown bodies. (Reference 2). The mature larvae now start As they feed on foliage, the larvae grow rapidly and reach maturity about 40 days after emerging from hibernation. The brown-headed, mature larvae have two distinct pair of white spots on their olive-brown bodies. The mature larvae start weaving a net with their silk on their last feeding spot or on other areas of the tree. They pupate for about 10 days. net with their silk on their last feeding spot or on other areas of the tree. This last pupal of the larvae lasts for about 10 days. (Reference 1)