Pine Saw Fly, aka "Worms Eating My Pine Tree"
European Pine Sawfly
While it is called Pine Saw-fly , it causes damage while in its larval stage. The larva are found in mass on pine. They eat the pine needles from the tip down. If something is eating your pine trees, these worms might be the culprits.
How to Diagnose: The mature larvae have shiny black heads and are grayish-green. They have a light stripe down the middle of their back, and a light stripe along each side followed by a dark green stripe running parallel down the length of their body. Newly hatched larvae are 1/8" long but measure one inch long when mature. The adults are brownish black and wasp-like. The cream colored eggs are deposited by the female in the current season's needles, but are not easily seen until they increase in size just prior to larvae emergence in spring.
Symptoms: Mass quantities of greenish-grey larva w/black heads, missing needles.
Recommendation: We recommend using Captain Jack’s Dead Bug Brew – it is a great biorational insecticide that will effectively kill sawflay with minimal damage to beneficial insects and the environment. Eight is a chemical insecticide from Bonide that will also kill them.