INVASIVE INSECTS THREATENING ILLINOIS HABITATS Oak Splendour Beetle (Agrilus biguttatus)
NATIVE TO: Asia CURRENT DISTRIBUTION in Illinois: Has not been found in North America IDENTIFYING cHARACTERISTICS: The larvae of the oak splendour beetle are white, legless and about 1-1 ¾ inches in length. They have two hornlike projections on their last abdominal segment. This insect pupates in the bark. The adult beetle is slender, metallic green in color with a distinctive white mark on its wing cover. These beetles are approxi- mately 1/3 to ½ of an inch in length. IMPORTANCE: The oak splendour beetle poses a substantial risk to both natural and urban environments if it were to be introduced. Damage manifests itself through crown dieback, epicormic sprouting (sprouting along the trunk) and eventually tree death. This insect preys on oak and occasionally beech and chestnut trees. Oaks are important landscape trees as well as essential trees in the lumber industry. The presence of the oak splendour beetle could have a significant ompact on the economics of this industry in the state. Life cycle: The oak splendour beetle usually produces one generation in two years, although in warmer climates it may only take one year. Adults emerge between May and August to feed on the crown foliage. The females also lay eggs in the bark crevices during this time. The larvae will hatch from the eggs in one to two weeks and begin boring zig-zag shaped galleries in the bark. The larvae overwinter in the bark for one or two winters and then pupate in the spring before emerging as adults, creating D-shaped exit holes on the trunk of the tree.
Above: Adult oak splendor beetle
Near Right: Oak splendour beetle Larva
Far Right: Gallery left in tree bark by oak splen- dour beetle larvae
ILLINOIS COOPERATIVE AGRICULTURAL PEST SURVEY
Photo Credits: Courtesy of invasive.org