White Pine Sawfly
Hosts: White pine is the primary host, with pitch, shortleaf, red and Swiss mountain pines attacked occasionally
Evidence: Look for pale yellow larvae with black heads and four rows of black dots going down their length (a). Larvae are present from July through August. Look for defoliation caused by gregarious feeding on old and current foliage.
Life Cycle: There is one generation per year. Insects overwinter as prepupae in cocoons in the topsoil. Pupation occurs in spring. Adults emerge and lay eggs, and larvae feed through September.
Management: Ornamental, plantation and forest trees of all sizes are attacked and maybe completely defoliated because this sawfly feeds on current and previous years' foliage. In some cases, natural control has been attributed to a wasp that parasitized eggs. Bacillus thuringiensis cannot be used successfully, but various chemical insecticides are effective against larvae.
Figure a: E. Bradford Walker, Vermont Department of Forests, Parks and Recreation, Waterbury, VT.
Drooz, A.T. 1985. Insects of Eastern Forests. USDA Forest Service Miscellaneous Publication 1426. p 390;
Johnson, W.T. and Lyon, H.H. 1991. Insects That Feed on Trees and Shrubs. 2nd edition. Cornell University Press. p 16-19;
Martineau, R. 1984. Insects Harmful to Forest Trees. Agriculture Canada Government Publishing Centre, Supply and Services, Ottawa. p 72;
Rose, A.H. and Lindquist, O.H. 1973. Insects of Eastern Pine . Canadian Forest Service Publication 1313. p 56