The balsam woolly aphid, Adelges piceae (Ratz.), first recorded in Newfoundland in 1949, is now the most serious forest insect pest in the Province, having spread over an area of more than 1,600 square miles. Its host is balsam fir, Abies balsamea (L.) Mill. There are three separate infestations, the largest and most important being in southwestern Newfoundland. The aphid has two generations a year. A biological control program was initiated in 1952 and seven species of predators have been released, three of which are established. Silvicultural and climatic control factors are discussed and the possibilities for the extension of outbreaks are considered.