Every year we look forward to spring with its burst of green growth. But shortly after the leaves appear, so do the cankerworms.
Cankerworms travel down from the trees, hanging on silken threads.
We all know that a stroll under an infested tree canopy is a very unpleasant exercise. Cankerworms are caterpillars that feed on the leaves of many trees including elm, ash, Manitoba maple, linden, oak and ornamental trees. They create small holes in the leaves but during severe outbreaks, trees may be completely stripped of leaves. This weakens the tree as it must develop a second set of leaves, usually by mid July. However, growth may be slower and resistance to other insect attacks and disease declines.