Aphis spiraecola is a recently found pest on apple in Bulgaria, where it develops in the absence of secondary hosts. The aphid has displaced the native species Aphis pomi DeGeer in some regions of the country. Its development, from newborn nymph to adult female takes, in laboratory conditions, 9–10 days at 22–24°C or 6–7 days at 28–30°C. The average fecundity of one female at both temperatures is 9.5–10.5 nymphs. Under field conditions, in May and July of 2007 and 2008, the full development lasted 8.1–8.6 days of average, and the average fecundity of one female was 20.7–21.2 nymphs. About 67% of them became adults, but more than 20% of the females died without having progeny. Theoretically, the species could develop twenty and more generations per the vegetation period of apple.