The green peach aphid (Myzus persicae) is a pest of peaches and nectarines throughout New South Wales. During October and November the aphids infest the young leaf growth causing the leaves to curl and shrivel, and in severe infestations trees may be rendered unproductive.

During the spring the aphids multiply rapidly, wingless young-bearing females being produced, and it is these aphids which cause serious damage to the young foliage. In early summer, as the growth is hardening off, winged aphids develop and migrate from the trees to various plants such as potatoes, cabbages, etc. They spend the summer on these secondary food-plants, and in late autumn, during May, winged females, and winged males fly back to the peach and nectarine trees.

In inland districts the females produce a generation of wingless egg-laying females which mate with the males and laterlay eggs, which carry the pest through the winter months. Many eggs may also be laid on cherry trees, and these hatch, but the aphids fail to survive.

The eggs commence to hatch in late July, and hatching is completed by about mid-August. The young aphids remain on the buds, growing in size, but not reproducing until the buds have burst. They then give rise to enormous numbers of living young in early October, as the trees come into leaf. In the warmer coastal areas the autumn migration to the trees does not occur and thus eggs arc rarely seen.