Trees weakened by drought, insect defoliation, or other factors are most susceptible. Larvae mine the cambium, resulting in girdled trees. Mortality can be extensive in weakened stands. Identifying the Insect. Identifying the Injury.
Attacks usually begin in the upper tree canopy and extend downward as the tree continues to weaken.
D-shaped adult emergence holes are evidence of infestation. Larvae in galleries. Photo by James Solomon Biology. Eggs hatch in 10 to 14 days. The larvae burrow through the bark and cambium.