About this Tree Concern
The Black Pineleaf Scale, is a scale insect that primarily affects pine trees, including Austrian, Scotch, and mugo pines, white fir and Douglas-fir trees. Adult scales are about 1.5 mm in diameter, oval, and have a gray to black shell with a yellow-orange crawler stage.
Pineleaf scale feeds on sap from needles, causing yellowing or wilting, needle drop, thinning crowns, and potentially tree death if the infestation is severe. They overwinter as immature scales, mate in June, lay eggs in late June and early July, and have crawlers present from mid- to late July. There is typically one generation per year.
Remediation
Keeping trees healthy and stress-free is vital. Monitoring scale populations and applying horticultural oil or insecticides during the crawler stage can help manage the infestation.