Spotted alfalfa aphid

Adult spotted alfalfa aphids are pale yellow-green in colour and about 2 mm long. They have 6 or more rows of tiny black spots on their back, which are just visible to the naked eye. The spotted alfalfa aphid is a pest of lucerne and annual medics, normally found on the underside of leaves. Nymphs are similar but smaller in size. Adults and nymphs suck sap and inject a toxin into the plant. Initial symptoms are a yellowing or whitening of the leaf veins. Damage proceeds from the base of the plant upwards, until only stems remain standing.