Following a period of relative inactivity in the winter, adults begin to fly again in the spring. Females land 6 to 30 feet above the ground on mature trees and bore into the bark. There, they create galleries in which they mate and lay eggs. The yellowish white, legless grubs feed in the inner bark, enlarging their tunnels as they grow. Mature larvae move to the outer bark and create a cell in which they pupate.
New adults chew through the bark, leaving small, clearly visible, open exit holes.
Adult emergence may continue for an extended period of time. When adults successfully attack a new host tree, they produce a pheromone or chemical scent that attracts other males and females. Within a few days, thousands of beetles may attack a tree and overwhelm its defenses. Obvious signs of infestation include white pitch tubes, running pitch, sawdust at the base of the tree, and many small emergence holes in the bark. Larvae chew curved or S-shaped galleries under the bark in the inner bark and cambium layer, and can girdle and kill the tree.