The newly formed adults tunnel through the outer bark, creating circular exit holes about 2mm in diameter. They then fly to the crowns of living, healthy pine trees of all ages, but prefer the taller trees in any particular area. Adults feed primarily inside lateral shoots, mostly in the upper half of the crown from May through October. During this period of maturation-feeding, each adult may destroy 1 to 6 shoots. Scotch pine is preferred, but other pine species have been infested in the Lake States including Austrian pine, eastern white pine, red pine, and jack pine.
Adults usually enter shoots in the one-year old or current year's growth.
Normally, one beetle infests each shoot. They tunnel into the center and bore outwards, hollowing out 1 to 4 inches of the shoot. After several weeks, adults often emerge and enter other shoots. Infested shoots generally bend near the point where the beetles entered, turn yellow to red, eventually break off, and fall to the ground. In the Lake States, adults exit twigs soon after the first frosts in October and November and enter the thick bark at the base of pine trees to spend the winter.