The oleander aphid is an obligate parthenogenetic species; thus the adult aphids are all female and males do not exist. Adult females may be winged or wingless. The winged adult females (alata) are yellow and black with dark wing veins while the wingless forms (apterae) are yellow with black cornicles, antennae, legs, and cauda (tip of abdomen). Nymphs are similar to apterae in appearance except that they are smaller. Size ranges from 1.5 to 2.6 mm in length.
Females are viviparous and parthenogenetic, meaning that they deposit nymphs rather than eggs and that the progeny are clones of the adult female. The nymphs feed in colonies on the shoots at the top of the plant. Nymphs progress through five nymphal instars. Normally apterous (wingless) adults are produced but winged adults occur under conditions of overcrowding and when plants are senescing. The parthenogenetic mode of reproduction, high fecundity, and short generation time allow large colonies of oleander aphids to build up quickly on infested plants.