Agrilus biguttatus

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Order	Coleoptera
Suborder	Polyphaga
Infraorder	Elateriformia
Superfamily	Buprestoidea
Family	Buprestidae
Subfamily	Agrilinae
Tribe	Agrilini
Genus	Agrilus

Scientific Name

Agrilus biguttatus

Common Name

oak splendour beetle

Joseph LaForest, University of Georgia

Distrubution

Oak splendor beetle can be found in Europe (north to southern England), Middle East, Siberia and northern Africa. It has not been reported in North America.

Host Range

This beetle mainly on oak but chestnut and beech are also susceptible.

Identification

Eggs are laid in bark crevasses in clusters of 5-6 eggs. The larvae are creamy white, legless grubs around 25-40 mm (1-1 3/4 inches) in length when mature. The first thoracic segment is wider than the other body segments. Two horn/pincer-like projections (urogomphi) are found on the last abdominal segment. The pupae are white and can be found in chambers within the bark. Adults are attractive, metallic green, slender; 8-13 mm (1/3-1/2 inch) in length; present May to July. The end third of the wing covers have two distinct white marks on the inside edge.

Life cycle

This beetle may have one generation a year in warm climates, but a two-year cycle is more common. Like other metallic wood-boring beetles, including emerald ash borer, they are strong fliers which are able to fly several kilometres in search of a suitable host. Adults engage in some maturation feeding in addition to laying eggs. The south side of large oaks (diameter at breast height of 30-40 cm (11-15 inches)) is preferred for oviposition. Larvae feed in the cambium creating frass-filled 'zig-zag' galleries. Pupation occurs in the bark. The insect overwinters in both the larval and pupal stages. In mid-spring, adults emerge leaving D-shaped exit holes.

Plant Response and Damage

Dieback, development of epicormic branches, thin crown, and tree mortality are typical. This is due to the destruction of the cambium. Callus growth and bark cracking may be observed as the tree attempts to compartmentalize the injury.

Gallery

References

• Exfor Fact Sheet
• Exotic Forest Insect Guidebook 2006