oak splendour beetle

Agrilus biguttatus (Fabricius, 1776)

Oak splendor beetle is native to Asia. It has not been found in North America. Like other metallic wood-boring beetles, including emerald ash borer, they are strong fliers which are able to fly several miles in search of a suitable host. They are readily moved in wood products such as firewood or other materials with attached bark. Oak is the primary host, but chestnut and beech are also susceptible. This beetle may have one generation a year in warm climates, but a two-year cycle is more common. Adult females feed on oak foliage before depositing clusters of 5-6 eggs in bark crevasses. The south side of large oaks (diameter at breast height of 11-15 inches) is preferred. Larvae feed in the cambium creating frass-filled, ‘zig-zag’ galleries. Mature larvae are creamy white, legless grubs around 1-1 3/4 inches in length. The first thoracic segment is wider than the other body segments. Two hornlike projections (urogomphi) are found on the last abdominal segment. Pupation occurs in the bark. The insect overwinters in both the larval and pupal stages. In May to June, adults emerge leaving D-shaped exit holes. Adults are attractive, metallic green, slender insects about 1/3 to 1/2 of an inch in length. The posterior third of the wing covers have two distinct white marks on their interior edge. Damage typically results in dieback, development of epicormic branches, thin crown, and tree mortality.

Identification, Biology, Control and Management Resources

Xilofág rovarok - Xylophagous insects - Hungarian Forest Research Institute
Exotic Forest Pest Information System For North America - North American Forest Commission