Neodiprion pinetum

The main host for the larvae of this species is the white pine (Pinus strobus), but it also occurs on the pitch pine (Pinus rigida), short-leaf pine (Pinus echinata), the red pine (Pinus resinosa) and the Swiss mountain pine (Pinus mugo).^[4]

The adult sawflies appear in late spring. The female uses its ovipositor to cut a slit along the edge of a pine needle and lays several eggs in this. If mating has occurred, both male and female offspring develop, but unmated females can also lay viable eggs, and these result in entirely male offspring. Each female lays about one hundred eggs over the course of a few months. The first instar larvae are gregarious and consume the surface layer of the needles but later instars spread out through the foliage and consume the whole needle. They feed on both old and young pine needles;^[2] heavy infestations can seriously defoliate the tree and isolated clumps of white pine can be killed.^[5] When the larvae are fully developed, they descend to the ground where they make cocoons among the leaf litter; in these they overwinter as non-feeding prepupae, pupating in the spring and emerging as adults a few weeks later.^[2]

Several parasitic wasps attack the larvae of this sawfly, and the egg parasitoid Closterocerus cinctipennis was found to be 90% effective in controlling an outbreak of the pest in Crawford County, Wisconsin.^[5]