Aphids are common pests of ornamental plants and the oleander is no exception. Oleander aphids are also known as milkweed aphids, which commonly feed on oleander, Nerium oleander, scarlet milkweed, butterfly weed and wax plant, according to the University of Florida, IFAS Extension. Oleander aphids appear on oleanders in the early spring.
Oleander aphids are brightly colored in yellow and black, and female aphids are either winged or wingless. Winged females are known as alata and wingless female aphids are called apterae. Nymphs are smaller versions of apterae and are yellow as well. Aphids are tiny insects and measure less than 3 mm in length, states the University of Florida, IFAS Extension.
According to the University of Arizona College of Agriculture, oleander aphids rarely cause significant damage to oleanders. Light aphid infestations are often beneficial because many other animals and insects feed on them. Heavy infestations are best managed by spraying oleanders with forceful streams of water, which knocks aphids from the shrub. Spraying affected oleanders with a mixture of water and liquid dish detergent may also eliminate aphids.