Order:  Homoptera

Family:  Adelgidae

Latin Name:  Adelges piceae Ratz

Common Names:  Balsam Woolly Adelgid, Balsam Woolly Aphid

Introduction
Top

The balsam woolly adelgid is an imported pest of the balsam fir forest. First accidentally introduced to Nova Scotia in 1910, the adelgid is a tiny sucking insect that distorts and kills balsam fir trees. There are two types of injury that may occur: stem attack, which may result in mortality; and twig attack, causing deformities to small branches. This twig deformity is known as gouting.

Life History
Top

In Nova Scotia, the balsam woolly adelgid usually has two generations per year. During winter, the adelgid survives as a dormant nymph under bud scales, in crevices of the bark, at the bases of buds, and at the branch nodes. In the spring, the nymph resumes feeding and moults 3 times. After these three moults, it becomes an adult and begins to produce white, waxy wool on its body. The females begin laying approximately 30 - 80 eggs during the first part of May. The eggs hatch within 1-2 weeks and a mobile nymph emerges and searches for a suitable feeding site. This young nymph or "crawler" is the only mobile stage of this insect. After it inserts its mouthpart, called a stylet, into the tree it remains stationary until death. Feeding continues throughout the summer. By late summer, this generation of adelgids is laying eggs that will eventually become overwintering nymphs.

The insects are dispersed by wind, birds, mammals, and the young crawlers moving around on the branches in the forest canopy.

Damage Symptoms
Top

The gouting results in distorted stems and dead tops, making trees unsuitable for the Christmas tree market. Attacks on larger branches and trunks result in restricted growth, fibre, compression, and death.

Control Options
Top

To reduce the spread of this pest, remove and destroy infested trees preferably during winter. Christmas trees can be treated before the buds swell with insecticidal soaps or chemical insecticides.