European pine sawfly should be active at this time. The European pine sawfly is a pest of mugo Japanese black, red, and scotch pines. Larvae are dark green with a black head and closely align themselves along the needles so are very difficult to detect. European pine sawfly feed on last year's growth. They can defoliate needles rapidly as they mature. Hosts look sickly, growth is reduced and they have a "bottle brush" or "poodle tail" appearance due to removal of needles behind the new season's growth especially in the early instars. Small larvae feed on the surface of needles, causing them to turn brown and wilt. Larger larvae eat entire needles but do not feed on new growth. They usually occur in small clusters, if enough are present, they can consume most of the needles on the plant. Mature larvae will drop to the ground and pupate in brown paper-like cocoons that are blunt at each end. There is one generation each year. Plan to scout now--it is hard to see the 1st and 2nd instar larvae but they are easier to control and early control can reduce host damage. Control options include a host of materials such as sevin and the pyrethroid insecticides. Spot spraying works if you only have a few trees, but scout carefully to detect each colony. Remember sawflies are not caterpillars (although they resemble them) so B.t. will not provide control. Unfortunately, infestations often are not noticed until most of the larval feeding is finished.
European Pine Sawfly. Photo by Steven Katovich, USDA Forest Service, Bugwood.org.Information from the University of Delaware and University of Kentucky.
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