They introduce the blue stain fungus that once established is deadly to the tree. The larvae bore small channels off the galleries. Once the eggs are laid the adults may leave the tree to attack another. Trees may be killed singly or in groups, ranging from a few trees to several hundred acres. Adult beetles make downward directed galleries in the cambium.
Eggs are together and the larvae feed side by side, creating a large gallery.
There are two to four generations a year. Trees that are not completely girdled by the BTB larvae may survive attacks since BTBs do not carry the blue stain fungi. Use care when working around trees to prevent mechanical damage by landscape equipment, including string weed cutters. Have a protective mulch island around the base of the tree to keep equipment away. Keep construction equipment away from the plants so there is no damage to the bark and to keep equipment and materials off the root zone so the tree isn't further weakened.