Pacific flatheaded borer—Chrysobothris malis
Adult flatheaded borers are hard, dark, mottled beetles with a bronze cast. The larvae are light colored
and have a distinctive shape with a flattened enlargement just behind the tiny head.
Identification of species | Life cycle
Flatheaded borers attack aboveground portions of the tree 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 open. Emergence holes 3/16 inch wide appear in early
Keep trees healthy and vigorous. Protect young trees from
sunburn with whitewashing. Remove and destroy
infested wood immediately. Insecticide treatments are not recommended.