Green peach aphids

Agronomist, Hayden Lunn (Landmark), has reported green peach aphids (Myzus persicae) on canola crops near Berrigan, in the Riverina district of New South Wales. Hayden says about 20% of all seedlings can be found with 5 or more aphids. All crops are at the 2 leaf stage. Agronomist, Paul Parker (I&I NSW), has also observed aphids in emerging canola crops around Young and West Wyalong, in the South West Slopes district of New South Wales. Paul says summer and early autumn rainfall in many regions resulted in significant growth of weeds and volunteer crop plants which probably acted as alternative hosts for aphids. This ‘green bridge’ combined with the early sowing of many crops has favoured aphid survival and put many crops at risk of viruses.

The green peach aphid is a pest of many crops, but is particularly fond of crucifer vegetables, oilseeds and some pulses, such as lupins. Unlike cabbage aphids, which form dense clusters, green peach aphids are usually sparsely distributed within a crop, mainly on the undersides of leaves. Some populations are resistant to insecticides and growers are urged to rotate their use of chemical groups to prevent resistance from developing further.

Adults have an oval shape body, are approximately 3 mm long, and may be pale yellow-green, orange or pink in colour. Winged adults have a dark patch on the abdomen. Green peach aphids are most common in autumn and seldom cause economic loss to canola crops. However, they are an important vector of plant diseases such a cucumber mosaic virus and bean yellow mosaic virus (in some pulse crops) and beet western yellows virus (BWYV) in canola. Studies of the relationship between virus infection and yield have shown that when aphids arrive early in the season, a combination of BWYV and green peach aphids can cause yield losses of up to 50% in canola.

 Click here for images of green peach aphids.