Instead of eating the whole needle, they bite off the needle at the base. The needles are left hanging in a mass of silk. Damaged trees have a characteristic, reddish-brown colour. Yellow-headed spruce sawfly larvae have a yellowish or orange head with a light yellowish green body. The body has gray green stripes running lengthwise.
Damage first occurs on new needle growth.
As the larvae grow, they consume the older needles. They can completely strip trees. Damaged trees are ragged in appearance. These tiny flies are most likely the fruit fly , sewer fly or fungus gnat . Each fly comes from a different problem area in your home.