Large aphid populations may produce large amounts of honeydew as waste from the sap on which they feed. Honeydew excreted onto fruit will serve as a growing ground for sooty mold fungus, which will affect the finish of the apple. Untrimmed trees render favorable conditions for the aphids and greatly handicap methods of control. A cool, wet spring favors aphid development because it provides conditions unfavorable for aphid parasites and predators. A large proportion of the overwintering eggs do not hatch.
Males are scarce and make up only a small portion of the total population.
Many females deposit eggs before mating, and these eggs do not hatch in the spring. The aphid passes the winter in the egg stage. Hatching occurs early in the spring, about a week to 10 days later than the apple grain aphid and at about the same time as the apple aphid. The eggs hatch when the buds start opening in the spring, over a period of two weeks. They feed on the outside of the leaf bud and fruit bud clusters until the leaves begin to unfold.