Pine Bark Adelgid
Pineus strobi (Hartig), Phylloxeridae, HEMIPTERA

 


DESCRIPTION

Adult -The adult is a small, dark (purplish to yellow) adelgid covered with a white, flocculent wax.

 Egg-About 2.5 mm long and 1 mm wide, the egg is a milky to light yellow-brown color. As the embryo matures, the egg darkens.

 Larva-The nymph resembles the larger adult. At first naked and yellow, it soon darkens and begins to secrete white, waxy threads


BIOLOGY

Distribution-The pine bark adelgid occurs over most of the United States wherever white, Scotch, and Austrian pines grow.

 Host Plants -Found principally on white pine, the pine bark adelgid occasionally attacks Scotch, Austrian, and other pines.

DamageThis adelgid is more unsightly than injurious on older trees, but it may seriously damage newly planted trees in parks and recreational areas as well as small nursery stock. The needles turn yellow, and small trees may be stunted or killed.

Life History -Adelgids are among the most commonly reported insect pests of pines. Not true aphids, they are often confused with woolly aphids because of the woolly strands of wax they secrete as they feed. The most commonly encountered phylloxerid on conifers is the pine bark adelgid, which feeds primarily on eastern white pine. Pine bark adelgids overwinter in all stages, though usually as immature females. In late winter, development resumes and each female lays up to 24 eggs in a woolly mass. From these eggs develop both winged and wingless forms. On pines there are several different forms of immature adelgids (a characteristic of phylloxerids), but only the crawler stage and winged forms are capable of migrating. The stationary wingless forms continue to reproduce parthenogenetically all season. There are five or more generations per year. 


CONTROL

For specific chemical controls, see the current state extension service recommendations.

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