Flat-Headed Wood Borers
Order:
Coleoptera
Family: Buprestidae
Species: Buprestis lineata F.
Flat-headed borers, Buprestis lineata F., are not known to cause serious structural damage to wood. They are commonly found in the Eastern United States and are attracted to live trees that have been damaged, such as by disease, insect infestations and hurricanes. They can infest freshly cut logs with bark still present, but do not attack timber once it has been sawn into wooden beams or boards. Damage is usually the result of larval activity before the wood is sawn and planed.
Log homes, especially those
constructed from untreated pine logs, can contain beetle larvae that will
reach maturity. In these
situations, adult beetles can be observed in the warmer months.
Reinfestation is highly unlikely.
Biology and Habits
The boat-shaped adult Buprestis lineata has a metallic sheen, hence it’s often called the “metallic” wood borer. The elytra (wing covers) usually have brightly colored (brick red to yellow) irregular markings and roughened ridges. The adults usually measure ½ to ¾ inch in length.
Fertilized females deposit their eggs in the cracks and crevices in the bark of tree trunks or limbs. The legless larvae, typically cream in color, have well-developed, flattened plates on the upper and lower surfaces on the prothorax. The abdominal segments are small. Larval development may take two years or more.
Larvae bore under bark and then into sapwood, and can penetrate the heartwood. Their feeding activity creates extremely flattened galleries (tunnels) and frass consisting of fine sawdust-like borings and pellets. Typically, galleries under bark edges cover the outer sapwood in a serpentine design. The walls of the galleries are a scarred with fine, transverse lines somewhat like, but more coarse than, those in old house borer galleries. Frass from this feeding activity is salt-and-pepper colored. This fine frass may remain packed in the galleries even after the wood is processed.
Upon completion of its
larval development, a larva constructs an elongated pupal chamber near
the surface of the wood. The
emerging adult cuts the characteristic flattened oval exit hole, up to
¼ inch long in diameter, to escape from the wood.
Emerging adults can damage uninfested materials, such as roofing,
drywall and flooring that cover infested lumber or logs.
Attack in dry wood is uncommon.
Control
Infestations are rarely recognized until the adults emerge. Since reinfestation is minimal, remedial treatments are not normally necessary. For the most part, economic losses are incurred before the wood is graded and built into a structure.
Additional damage to the
structure may occur when the galleries function as water channels, capturing
rainwater and channeling it inside the wood, creating a condition conducive
for decay. Seal emergence
holes to prevent water damage to wooden members.
(Courtesy of the National Pest Control Association.)