The woolly apple aphid, Eriosoma lanigerum (Hausmann), is a reddish brown insect covered with a white wax mass produced by specialized dermal glands. This wax mass gives the insect its characteristic woolly appearance (fig. 1). The woolly apple aphid is distributed worldwide.
The most important form of injury caused by woolly apple aphids is root injury, consisting of galls at feeding sites (fig. 2). This root injury can reduce the growth of young apple trees; mature trees are affected to …