They settle down and content themselves with f eeding and producing young at a rapid rate. Production of young usually begins two or three days after the last molt and continues without interruption for over a month. A single female produces an average of about 185 young. Normally, the period of reproduction extends from about pink to June 20 or later. The maximum period of productive activity is usually around the last week of May and the first week of June, which is the period when young fruits are beginning to set and start active growth.
Populations are usually highest in the inner and upper parts of the canopy.
There are approximately three generations produced on apple, with the second generation occurring two to three weeks after petal fall and the third generation appearing by mid to late June. By early to mid-July all aphids have developed into alates and have dispersed from apple to summer hosts. About six generations occur on narrowleaf plantain during the summer before winged females fly back to apple in the fall. These females produce wingless oviparae, which mate with returning winged males from the summer hosts. Mated females deposit an average of four to six overwintering eggs, usually in late October and November.