Pine Needle Scale

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Pine needle scale is fairly common in the area. Scale can cover the needles with clusters of white flattened bumps. If there is a high population the needles may appear to be white. They can infest a number of different pines and spruce trees. The scale insect feeds on juices from the needles. A light infestation causes little damage. A heavy infestation can cause branches to die or in severe cases, kill the plant. The scales survive the winter on the pine needles as eggs beneath the dead mother scales. The eggs hatch in late spring and the young scales, called crawlers move to new green needles to feed.

For a mild infestation caught early, you can simply prune out infested branches. Dormant oil spray is effective when applied in late March or early April before new growth begins. The oil coats the scale and can suffocate the eggs. In the early summer, in May or early June, the crawler stage can be treated with an insecticidal soap or insecticides. You can examine the infested plants with a magnifying glass to see if crawlers are present. Contact your county Extension office, Master Gardener hotline or local nursery for information about insecticide use.

Reference: MU Guide G7274 Aphids, Scales and Mites On Garden and Landscape Plants

Tom Fowler, FowlerT@missouri.edu
Regional Specialist, Agriculture and Horticulture
Buchanan County, MO
University of Missouri Extension