Larvae spin webbing among the needles of expanding shoots, and feed until disturbed or the shoot is completely destroyed. When feeding on new foliage early in the summer, budworms construct a shelter by binding the needles together at the tips with webbing. They retreat to this shelter when disturbed. In midsummer, they pupate either in their feeding webs or in other webs in the foliage. Adults emerge from the pupae and fly to seek a mate.
Dispersal redistributes budworms within the crown and between trees and stands.
It may occur at any point in the life cycle, but most commonly it is the younger larvae that are carried by the wind to other trees. This can be significant as the tallest trees are preferred by the egg-laying adults, and larvae are blown to shorter, intermediate or overtopped trees. Adults are also dispersed by wind currents and over a long range by frontal systems. Physiological stress in host trees influences susceptiblity to attack and concurrent damage to a high degree. Nonvigorous trees are more susceptible to attack and receive more damage than vigorously growing trees.