RWA are small, pale green in colour, elongate and spindle-shaped, often with a fine dusting of whitish wax. Apterous (wingless) adults have very short antennae, about 0.33 to 0.5 body length, and very short siphuncles ('exhaust pipes') which initially appear absent to the naked eye. The alate (winged) adults are small, up to 2mm in length, with body-length antennae and are generally darker in colour with dusky colouration on parts of the body, particularly the thorax. They have two 'caudal processes' (short tails) on the end of the abdomen, one above the other, giving the appearance of a 'double tail'. Their general small size, green colour, elongate shape, very short antennae and apparent lack of cornicles are characteristics that can readily distinguish RWA from other aphids found in Australian cereal crops.
More information on distinguishing characteristics of RWA appear in the GRDC I SPY manual (Page 39)