Origin:
This beetle is a native insect in western North America, from Mexico to British Columbia.
Biology:
This is considered to be one of the most destructive of the bark beetles, with 10 or more species of pines known to be fed upon and killed by it. The adults attack living trees and bore egg galleries in the cambium that may be up to 3 feet long. The larvae then chew feeding channels outward from the egg gallery, easily girdling trees when the infestation is heavy. In addition, a fungus may be introduced when the adult beetle enters and this fungus is capable of further blocking the vascular system of the tree. Trees typically turn brown and die the following year. There is one generation of the beetles each year.
Identification:
The adult beetle is about 5 mm long and black. The head projects somewhat forward from the prothorax and is visible from above. The antennae are typical of bark beetles with several very small and short segments and a much larger, rounded terminal club.
Characteristicts Important to Control:
In a landscaped environment single trees may be protected with preventive sprays applied to the bark just prior to the emergence and activity of the adult beetles. Systemics may have some success applied either to the soil in the root zone or as trunk injections. In a forest environment the losses of trees to this beetle can be staggering, and control is nearly impossible in forests weakened by drought. Discovery, removal, and burning of infested trees is one method used to control the spread.
