Aphids are small pear-shaped insects with thread-like antennae and a pair of tube-like structures (cornicles) on the abdomen. Most individuals are wingless but some individuals have two pairs of membranous wings that are folded in a roof-like fashion over their abdomens. Adults are 1.5 mm in length and can vary in body colour from light green to cream. The head and thorax are darker than the abdomen and the body is covered with a fine white powder.
Nymphs look like wingless versions of adults.
Aphids are sap feeders that use their straw-like mouthparts for puncturing plant tissue. Feeding causes leaves to become discoloured and disfigured. Typical injury results in small, curled leaves with reddish streaks. In heavy infestations leaves may be covered with honeydew and have a shiny appearance. Black mould may develop on leaf surfaces covered with honeydew. Aphids also can leave white cast skins on leaves and stems.
Eggs hatch in early spring just after buds being to break. The first couple of generations give rise to wingless females through parthenogenesis (females producing female offspring without mating). In late summer winged males and females are produced. These individuals mate and lay eggs that overwinter. Eggs are usually laid on buds or branch tips.