There are several species of needle miners. Spruce needle miner (Endothenia albolineana) attacks most types of spruces. Eggs
are laid like shingles on the spruce needles. After hatching the
larva enters the base of the needle, hollowing it out. The larvae
cut the needles off after completely mining them. Dense mats of
silk threads hold the dead needles on the twig. Larvae feed on one
needle after another till fall. At this time, the larvae over-winter
inside a needle. They emerge in the spring and feed till they pupate.
Apply an insecticide in early spring. Check with your local land grant university (Cooperative) Extension Service for recommended insecticide.
Written by James Schuster, Extension Educator, Horticulture, and reviewed by Dr.Philip L. Nixon, Extension Specialist-Entomology, Department of Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign.