Moss Like Insects on Pine

Identification

• Insects resembling moss on a pine tree are likely the pine bark adelgid, a pest that covers itself with a white, waxy secretion. They live within the branches and bark and occasionally spread to the needles. An infested tree appears as if it is covered with a collection of cottony mold. The pest is tiny, approximately 1/32 inch in length, and a dark-red or purple color.

Features

• The adult pine bark adelgid has two pairs of wings and lays yellowish-brown eggs hidden beneath the white, waxy covering. Upon hatching, yellow crawlers emerge, begin darkening in color and mature. Because as many as five generations of this insect are produced annually, so the white covering on the pine tree grows rapidly.

Emergence

• The female, adult pine bark adelgid overwinters in the tree's bark and crevasses before laying her eggs underneath her body in late winter. The crawlers emerge in May. Pest populations are at their highest in the spring and fall, when their natural predators are fewer. Crawlers may move from plant to plant via wind currents or even by birds. Once they begin feeding, the crawler stays in place until the next molting.

Management

• Damage by the adelgid to a pine tree is primarily aesthetic among older trees, but heavy infestations may cause fatal injury or stunting immature trees' growth. The first symptom is a yellowing of needles, as feeding denies nutrients to the tree's extremities. Lady beetle larvae and fly maggots are natural control agents against the pine bark adelgid. For severe infestations, apply horticultural oil in the spring.