Apple Mealybug

Phenacoccus aceris

Despite the common name of “apple” mealybug, this insect is by no means a specialist. The host range is very broad, including all deciduous fruit and nut trees (apple, cherry, pear, plum, apricot, filbert), small fruits (grape, currant, gooseberry, blueberry) many shade trees (maple, oak, birch, willow, ash, linden, elm, mountain ash) and various ornamentals (cotoneaster, hawthorn, quince, spirea). The alternative common name, the polyphagous tree mealybug, is more indicative of this broad host range.

The adult female is 3-4 mm long, with a sage green body color visible through the white waxy coating. The tailson the caudal end of the mealybug are shorter than those of grape mealybug, and the body color (green vs pale purple) distinguishes it from grape mealybug, the most common mealybug pest in Washington tree fruits. The male is a typical of the Coccoidea, winged and relatively delicate.

Sucking sap will to some exent devitalize the tree, although this is probably the least of management concerns. Like most sap-feeders, this insect produces honeydew (a high-sugar fluid excrement) that can serve as a substate for sooty mold. The production of honeydew which can drip on fruit is of more concern, and more likely to require control. In addition, apple mealybug can also directly infest and feed on fruit, possibly becoming a direct pest or quarantine concern.