Check for aphids on aphid susceptible trees and shrubs
When lilacs show purple flower clusters, look for aphids on aphid-susceptible trees and shrubs such as ornamental fruiting Plum, Caragana, and Spirea. White, fluffy aphids at the base of new buds on Douglas Fir and Spruce are the Spruce Gall adelgids that cause pine cone-like galls. Treat if 50% of branch tips are infested.
