A female produces young aphids about 1 day after its final molt. The four nymphal instars develop within 2 weeks. As many as 16 generations can be produced in 1 year. The apple aphid is most abundant from mid-June to the beginning of August. In early September, male and female aphids appear and mate.
Mated females deposit one to six eggs, which develop partially before the first frost.
Populations of the apple aphid undergo fairly regular fluctuations in density throughout the summer. Because the aphid feeds only on new growth, the density of the populations is regulated somewhat by the growth of new shoots.