Polygraphus rufipennis (Kirby), a phloeophagous bark beetle associated with Abietineae hosts in northern and mountainous areas of North America, is particularly prolific in the boreal forests of Newfoundland. Projected wood shortages in Newfoundland have focused attention on the ecological role of P. rufipennis in stands of black spruce, Picea mariana (Mill.) B.S.P., weakened by eastern spruce budworm, Choristoneura fumiferana (Clem.). Significant relationships between P. rufipennis attack and cumulative budworm damage in mature stands of black spruce were evident in both time and space. The highest incidence of attack occurred in severely damaged stands in 1983 with 32.6% of the trees successfully attacked. In 1984 and 1985 the proportion of newly attacked trees in severely damaged stands decreased to 16.6% and 6.0%, respectively. In stands of moderate budworm damage the proportion of trees attacked by P. rufipennis decreased from 13.5% in 1983 to 6.7% in 1984 to 5.1% in 1985. The proportion of trees attacked by the beetle in lightly damaged stands varied little over time with 2.1%, 2.9% and 2.2% of the trees attacked in 1983, 1984 and 1985, respectively. A significant trend between attacked trees and time was evident in moderate and severe damage, coupled with a significant dependency of beetle attack on defoliation level. Logistic regression identified crown damage, height, and diameter, as key characteristics significantly associated with beetle attack in both moderate and severe damage categories. The results of baited-tree experiments confirmed a priori expectations of greater attack success on trees in higher damage classes. The implications of secondary bark beetle activity on black spruce successional patterns is discussed.