We recently received reports from Dave Feltes, IPM Extension Educator, of white pine sawfly larvae causing damage in Carroll County in the northwestern corner of the state. This insect feeds on both the young and older needles of white pine, mugo, and red pines. Completely defoliated branches or trees will die, so control is important.
The larva is about one inch long with a large black head. The body is yellow with four rows of black dots down the back and sides. When fully grown, the larva drops to the soil where it pupates to emerge as an adult, wasplike insect the following year. This sawfly is easily controlled with many chemical insecticides.