Pine sawflies
Natural History
Female red-headed sawfly laying eggs
Photo credit: J. McGraw - North Carolina State University
Pine sawflies are insects in the genus Neodiprion or the genus Acantholyda that defoliate pines in Florida and throughout the South. There are currently around eight different species of sawflies in Florida. Sawflies usually attack only one tree or a small group of trees. Under favorable conditions, attacks by sawflies can intensify and the insects can infect thousands of acres of trees.
Sawflies prefer 5- to 10-year-old trees. Repeated attacks over 2 or more years can cause a tree to die but the greatest damage caused by pine sawflies is loss of tree growth. They create this damage by eating the needles of pines.
In the spring, female sawflies lay their eggs in the needles of pines. The female cuts an individual slit for each egg and can create 1 to 30 slits for eggs in one needle. Larvae hatch from the eggs to eat the pine needles. Fully-grown larvae drop from the needles to the ground and spin cocoons in the soil. Sometimes larvae do not drop from the tree but remain to spin their cocoons in the branches and needles of the tree. This is common when the ground is flooded. Adult sawflies emerge from the cocoon weeks, months, or even years later depending on the species.