Adult borers are beetles that are often metallic (coppery, blue, black, or green), particularly on the
lower surface and upper abdomen. Their bodies are flattened, elongated or oval, and typically have longitudinal
grooves on the wing covers. The larvae are light colored and have a distinctive shape with a flattened
enlargement just behind the tiny head.
of species | Life
Flatheaded borers attack aboveground portions of trees that have been previously injured by sunburn or
other causes. Tunnels excavated beneath the bark by the borer larvae may cause a wet sappy area on the
bark of the main trunk, which may later crack. Limbs or trees may be killed.
Prevention is the most effective management.
Stressed trees are most likely to be damaged. Properly plant
species that are well adapted to that location and provide
them with proper care. Avoid pruning from spring through
summer when adults are active. Protect trees from injury.
Remove and dispose of dying limbs and dead trees. Do not
pile fresh-cut wood near trees; beetles may emerge from it
and attack nearby plants. Provide proper irrigation. Sprays
are not generally recommended, but may provide some control
adults of alder and bronze birch borers.
Pacific flatheaded borers larva
bark caused by the flatheaded borer