Entomology

Pine Pests

Our two major pests of pine trees should be controlled now if population densities warrant treatment. European Pine Sawfly larvae will become more noticeable as they rapidly approach their 1-inch length. Of course, feeding damage to the old needles by the clusters of gray-green "worms" also becomes more noticeable the longer you wait. Mechanically remove or prune away larvae, or spray with Sevin, Orthane or horticultural oil (the last choice most effective against small larvae).

Lilacs have bloomed and spirea is in bloom, so Pine Needle Scale eggs should be hatching. The first instar nymphs ("crawlers") are vulnerable now to sprays of horticultural oil, insecticidal soap, Diazinon, Orthene, Sevin, and other labeled insecticides.

This article originally appeared in the May 22, 1991 issue, p. 95.


Prepared by Donald Lewis, Department of Entomology
Iowa State University, Ames, Iowa.
This information subject to a usage policy.
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Last updated 12/12/97 by John VanDyk
http://www.ipm.iastate.edu/ipm/hortnews/1991/5-22-1991/pine.html