An accurate and efficient survey method is essential to ensure the proper regulatory and management decisions for Tomicus piniperda (L.), a recent bark beetle invader in the United States. The life cycle and cryptic habits of T. piniperda make its detection difficult. T. piniperda adults feed in shoots in the summer, overwinter in the bark at the base of live pine trees, then oviposit into galleries in the bark of dead or dying trees. In 1992 and 1993, we characterized shoot damage and overwintering behavior of T. piniperda in the Great Lakes region of the United States. Shoot-feeding tunnels of T. piniperda were detectable in 7.4% of the shoots of Scots pine trees, Pinus sylvestris , sampled in northern Ohio in early October 1992. Adults of T. pinipenla fed primarily in the upper third of the tree crowns. Live T. piniperda adults were present in the majority of shoots that exhibited discolored needles and drooping shoots. However, many shoots with T. piniperda adults present exhibited no visible symptoms of attack. In early October, live adults were more common in tunnels constructed in current-year shoots than in 1-yr-old shoots. Scots, white ( P. strobes ), red ( P. resinosa ), and Austrian ( P. nigra ) pines attacked by T. piniperda developed yellow and brown needles, accompanied by drooping shoots only in Scots and white pines. In 1992 and 1993, the departure of T. piniperda adults from Scots pine shoots to their overwintering sites was correlated with subfreezing temperatures during latc October through December. Bolts of Scots, white, and Austrian pines were readily used by T. piniperda for overwintering sites, but bolts of blue spruce were not.