European pine sawfly larvae have already been reported in several parts of Iowa, and NOW will be your last chance to discover any defoliation in time to treat effectively. Defoliation of pine trees and shrubs by clusters of European pine sawfly larvae is a common problem during the month of May. Full grown larvae that are usually present by Memorial Day weekend, may be a little later this year. Look for 1-inch long grayish-green larvae with 2 light stripes and 1 dark stripe on each side of the body and shiny black legs and head.
Additional detail about pine sawfly was provided in the May 5, 1995 newsletter . Control larvae by pruning or shaking from trees, or spraying with Sevin, Orthene or Isotox if warranted. The larvae have only one generation per year and there is no justification for spraying after grown larvae have left the trees.
This article originally appeared in the May 26, 1995 issue, p. 78.