VT a. Larva of the Redheaded pine sawfly b. Red pine defoliated by Redheaded pine sawfly larvae.
Preferred hosts are red, Scots and jack pines.
Look for defoliation caused by larvae feeding gregariously on old and new foliage and tender bark. They tend to defoliate an entire branch before moving on another area of the tree. Fascicle sheaths or tufts of curled, strawlike needles may remain after larvae feed. There is one generation per year. Winter is spent as a prepupa in topsoil or duff.