Balsam woolly adelgid, Adelges piceae,
 

Fig. 43   Balsam woolly adelgid adults without tufts.	Fig. 44  Distorted crown resulting from balsam woolly adelgid attack.	Fig. 45   Stunted terminal growth from continual balsam woolly adelgid crown infestation.
Fig. 46,  Gouting due to infestation by balsam woolly adelgid.	Fig. 47  Wool-like tufts cover feeding balsam woolly adelgids.

Distribution:  Evidence indicates that all stands containing true firs within the southwest portion of B.C., including Vancouver Island, may eventually be at risk.

Tree Species Attacked: All true firs are susceptible, with amabilis and grand firs attacked most frequently. Grand fir is the most tolerant of attacks; sub-alpine fir is the most easily damaged. All ages are susceptible.

Insect Description and Damage Symptoms: Adults are tiny (less than 0.1 cm) and covered with wool-like wax threads. Masses of feeding adults, appearing as thousands (up to 100 per sq.cm) of tiny (0.1 cm av. diameter) tufts of wool, may be visible on the smooth bark of younger trees and in the bark crevices of older trees. Rubbing the wool tufts during summer months should produce a purple stain on the fingers. Crown-attacked trees have thin, chlorotic to red-brown upper crowns, stunted terminal growth, and possibly dead tops. Closer examination of the top will reveal swellings around buds and branch nodes, called "gouting". Decay fungi may be associated with these symptoms. Stem-attacked trees exhibit a general decline, with the entire crown being chlorotic to red-brown and possibly thin. Stem attack, however, is less common than, but always associated with, crown attack. This insect is difficult to see during the winter months. Therefore, diagnosis during winter should be based on gouting and crown symptoms.

Damage: Attacks occur most commonly on large trees, but all age classes of trees are susceptible. The intensity of attack will vary within an infested stand. Outbreaks have been associated with sites disturbed by logging, road building, or drought. Crown attack produces dead tops and growth reduction, but most trees can survive crown attack for several years. Stem attack has a more severe effect on the host tree, which may die following 2 to 3 years of repeated infestations. Wood quality is also adversely affected. 

Similar Damage: May be mistaken for damage caused by scale insects. Wool-covered females and gouts are distinctive.

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BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated March 12, 2002