Insects, earthworms and snails. Overwinters in all life stages. Following first emergence in spring, 3-9 generations can occur in one year. Females penetrate bark of hosts to form brood galleries. Chemicals released by male and female beetles attract many beetles to tree.
Healthy trees respond by bleeding pitch from attack holes.
Beetles make hole in center of these masses, creating a pitch tube. Hundreds of pitch tubes can be found on single tree trunk. Introduces blue-stain fungus into sapwood, inhibiting water flow in tree. Results in tree death only days after mass attack. Foliage fades from green to red.