The spruce budworm eats the tree’s needles and new shoots. Over three to five years, an infestation will kill the crown of the tree, if not the entire tree.Ģ. These mature budworms are responsible for 85% of all needle loss, or defoliation, caused by the insect. When new shoots appear, the larvae form a second cocoon-like shelter and feed off the shoots until late June when they mature into larger caterpillars. The larvae overwinter in small silk cocoons and emerge in the spring at only 1.5 millimetres long to feed on flower pollen as they wait for buds to open. It is found in all of Canada’s provinces and in the United States. The spruce budworm is a native North American insect whose caterpillar measures about 20 to 30 millimeters and is a voracious eater of conifer needles, specifically, those of white, red and black spruce as well as balsam fir.
What is the spruce budworm and where does it come from?
