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Stark-Billings County |
Extension Spotlites
June 18, 2009
Pine Needle Scale
I have received quite a few phone calls this past week regarding whitish specks on pine needles. Those are typically a sign of an insect called pine needle scale. Pine needle scales overwinter beneath the female scale covering as reddish eggs. Each female lays up to 100 eggs, which usually hatch in May or June. The tiny red crawlers or nymphs (1/80 inch) emerge and are dispersed by the wind to a new uninfested host or crawl to a new location on the same host. Young crawlers settle on the foliage, lose their appendages by molting, and begin feeding. Nymphs become sexually mature in late July and August and the adult scales emerge. Female adults are wingless, while male adults have wings and are smaller. After mating, the female lays eggs until late October. She shrinks in size as she lays eggs.
Scales suck juices from the needles. Moderate populations can cause the foliage to become yellow and then turn brown. Heavy infestation can cause branches and even whole trees to die. Symptoms include sickly looking trees with sparse, off-colored foliage and waxy white coverings over the scale insects. The scale cover looks like drops of white paint on needles.
Individuals should inspect ornamental trees for crawlers early in spring. Most populations can be managed by keeping hosts healthy along with timely applications of insecticidal oil or soap. Conventional insecticides such as acephate and malathion can be used; however, eliminating the scales' natural enemies with conventional insecticides can make the situation worse.
For more information contact:
Kurt Froelich,
Extension Agent
NDSU Extension Service
Stark-Billings County
1340 W. Villard St.
Dickinson ND 58601-4646
(701) 456-7665