Early in the summer, when budworms are feeding on new foliage, needles will be bound together at the tips with webbing. Defoliation is most obvious in the upper crown and at branch tips. Tree decline, topkill, and death may follow severe defoliation. Adult insects are orangish-brown triangular moths, a little less than an inch across. Egg masses on needles are pale green.
Pupae are golden-brown.
Eggs hatch in about 10 days. The larvae molt once, then hibernate for the winter on rough bark surfaces in the canopy and down the bole. In the spring, larvae re-emerge and begin to tunnel into older foliage, or float away on silken threads. After about two weeks, they move on to expanding buds and finish with the new foliage. Larvae spin webbing among the needles of expanding shoots, and feed until disturbed or the shoot is completely destroyed.