Spruce Budworm

The spruce budworm has a long history feeding on spruce and fir forests in our region. Occasionally, the population levels of the spruce budworm rise to infestation levels and result in severe damages and losses in wood supply. In June and July, when trees have new growth, the spruce budworm caterpillar is at its most destructive. After the caterpillar stage is over and the moths emerge, the infestation can spread as the moths disperse with the wind. Each female budworm can lay up to 200 eggs, making it possible for millions of moths to disperse over several kilometres in a single evening. A typical spruce budworm infestation may last up to ten years and the repeated feeding by the caterpillars may kill more than 80% of the balsam fir trees and 50% of the spruce trees.

Forests killed by the spruce budworm are very susceptible to forest fires. Dead trees may only be used to make lumber or pulpwood for a short period of time before they become too dry and rotted to use. The loss of growth and premature tree mortality has long-term impacts on the available wood supply for mills and communities.

In an effort to minimize the potentially devastating losses caused by this pest, scientists, governments, and industry are working together on an “early intervention strategy” to limit and control the spruce budworm. This initiative includes:

• Efforts to better understand natural budworm controls (parasites and predators).
• Using pheromones to confuse the moths from mating and laying eggs.
• Using new technologies for early detection at sites with rising budworm populations.
• Doing small area targeted spraying to control budworm caterpillar populations.

For more information about the spruce budworm, the status of the present infestation, and our research's work and results, visit: http://www.healthyforestpartnership.ca/