• Schooley, H.O.
  Newfoundland Forest Research Centre
  
• Oldford, L
  Newfoundland Forest Research Centre
  

The balsam woolly aphid is an important pest attacking all age classes of balsam fir, the most abundant pulpwood species on the Island of Newfoundland. A salivary substance injected into the tree by the aphid reacts on the cambium resulting in the formation of enlarged annual rings of brittle, reddish-brown wood.,"red-wood". When aphid attack is concentrated on the shoots and twigs, "twig attack", it causes a swelling of the nodes "gout", inhibition of the buds and eventually, a dying back of the branches. This condition is the most prevalent symptom found on aphid injured trees in Newfoundland. Tree mortality usually occurs only after a long period of such attack. When aphids are concentrated on the stem and/or the base of branches, "stem attack", the attack is recognized by white wax threads covering the feeding nymphs and adults. This condition is not common in Newfoundland, but when it does occur, it can cause death of infested trees in a period of only 2 or 3 years. Damage symptoms increase on trees under persistent attack. However, if the aphid infestation collapses, the trees released from damaging effects usually recover and resume normal growth.