This pine sawfly is found throughout the southeast from Virginia to
Texas. Loblolly and shortleaf pine are preferred hosts, but pond, slash,
longleaf, and Sonderegger pine are also attacked. The larvae do not do
well on the latter two species. As with most sawflies, the larvae feed
in groups on the host needles. Generally the old needles are preferred,
but all of the needles are eaten when large numbers of larvae are
present. Three or four young larvae usually encircle a needle and,
starting from the tip, consume all but a central core. When nearing
maturity they eat the entire needle.
[Illustration: Pine sawfly larvae.]
Four or five generations of this sawfly may occur each year. Adult
females begin to lay their eggs in slits cut in the needles during late
March. The eggs hatch in 10-21 days, and the larvae feed for about five
weeks. When mature the larvae usually crawl to the ground and spin a
cocoon in the loose litter at the base of the tree. Although all stages
of the life history can be found at any time during the growing season,
the peak adult emergence occurs in late summer. Larvae from this late
summer generation are responsible for most of the damage which, although
never directly responsible for mortality, may predispose the trees to
attack by other insects (particularly bark beetles) and diseases.
Natural control factors generally bring outbreak populations under
control after one season. Hogs, armadillos, mice, and shrews are
reported as being of significant value in regulating the sawfly
population. Insect parasites, predators, and disease are also effective
control agents.