Origin:
Native to North America.
Biology:
This is the largest aphid species occurring in the United States, and is found throughout the U.S. from north to south and east to western states. It infests a variety of hardwood trees, including oak, hickory, sycamore, willow, walnut, and pecan. Large populations can produce copious quantities of honeydew that drip onto surfaces below as well as sustain the growth of sooty mold. Their feeding can reduce the vigor and health of a tree, but whether or not they actually cause the death of trees is unknown. These aphids can be present on susceptible trees from mid-spring to the end of summer, although in the dry, arid southwestern states the heat of mid-summer may cause populations to go dormant.
Identification:
Adult females have an overall body length of around 1/4 inch with extremely long hind legs. The winged females are nearly twice that length overall. These are very broad, somewhat flattened insects with a gray body color with rows of black spots running front to back, and a large black spot in the center of the top of the abdomen. The cornicles are short and blunt. Large numbers of the aphids often mass together on the trunk and branches of a tree.
Characteristicts Important to Control:
Control for the sake of the tree may not be needed, but to reduce the copious amounts of dripping honeydew over vehicles or locations of human activity a control program may be needed. A foliar spray with a labeled product can be applied to the leaves, branches, and possibly the trunk of infested trees. A soil application with a systemic done in late winter will provide good control of aphids feeding on the foliage.
