COMMON PINE SHOOT BEETLE ( Tomicus piniperda )
The common pine shoot beetle, has been known as a pest of conifers in Europe and Asia for many years. Feeding causes death of shoots, loss of vigor and slowing of growth, a serious hazard to the timber industry. First discovered in North America in July of 1992, it has been most frequently reported on Austrian and Scots pine. Adult insects are roughly cylindrical and 3-5 mm long with shiny black heads and wing covers ranging from reddish brown to black. They resemble other common native bark beetles so positive identification should be made by trained experts. The Common pine shoot beetle has been found in six states: Illinois, Indiana, Michigan, New York, Ohio, and Pennsylvania.
Adults spend the winter in the lower stems. In the spring, they emerge and crawl or fly to nearby dead or dying pines where they mate and lay eggs beneath the bark. Eggs hatch, and the larvae remain under the bark to feed for 6-8 weeks and then pupate. Hungry adults emerge, and maturation feeding is done in young shoots of pines. Each insect makes a hole 2-3 mm in diameter in the bark, as a point of entry into the shoot, and mines the tissue within for up to 10 cm. When damage is sufficient to cause wilt of a shoot, the insect may lose interest in it and find another. Thus, one adult may take several "strikes" during the course of its lifetime.
On Scots pine, infested shoots become discolored, and may die as early as late June, though often remaining attached to the tree. On Austrian pine, infested shoots remain alive and green much longer. In early July, they can only be recognized when uninfested shoots expand to full size while infested shoots remain stunted. Close examination may reveal the entrance hole, often rimmed with resin, near the base of the affected shoot. Slit the twig open and you may find the adult beetle within in a frass-free channel.
Fig. 1. Entry hole to beetle channel in pine shoot.
Beetles breed in recently dead or dying pines. Culled pines should be chipped, burned, or buried to minimize their chances for serving as breeding sites and for contributing to buildup of beetle populations. Stumps should be treated as they would be for Pales weevils to further eliminate breeding sites. Wherever possible abandoned, overmature, or otherwise unmanaged pine plantings should be brought under management or destroyed.
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