Bluegreen aphids

Bluegreen aphids have been detected in high numbers in some pastures and lucerne paddocks between Narrandera and Griffith, in the Riverina district of New South Wales. District agronomist, Mary-Anne Lattimore (Industry & Investment NSW), reports finding damage on new shoots of mature lucerne and on established sub-clover, as well as high numbers of aphids on some seedling lucerne plants. Mary-Anne says there also appears to be a high level of aphid parasitism occurring, with numerous aphid ‘mummies’ being observed.

Pastures scientist, Alan Humphries (SARDI), has noticed more damage than normal on lucerne seedlings this year from bluegreen aphid. The damage has occurred on a range of lucerne cultivars, and has included plant death, which is not usually observed. Alan is asking farmers and agronomists to be on the lookout for unusual damage from bluegreen aphid in lucerne, and would like to hear from anyone that seen more than usual damage. SARDI scientists are monitoring the situation, and feedback will help determine whether further investigation is required. Alan can be contacted with photos or descriptions of damage via email alan.humphries@sa.gov.au or phone (08) 8388 7198.

Bluegreen aphids (Acyrthosiphon kondoi) are a large species, measuring up to 3 mm long as adults. Both the winged and wingless forms are a matt bluish-green colour. Annual medics, lucerne, subterranean clover and lupins are susceptible to bluegreen aphids. In lucerne and medics, heavy infestations cause stunted growth, leaf curling and leaf drop. In subterranean clover, leaves wilt before turning brown and dying. Bluegreen aphids favour growing tips of medic and lucerne, while in clover they are widely dispersed under the canopy. 

Click here for images of bluegreen aphids.

When considering control options for all aphids it is important to remember that in some cases the whole paddock may not require treatment, as infestations often start at crop edges. If most of the infested plants are along the edges of a crop, a perimeter spray is likely to control the majority of aphids. This approach will also preserve some of the beneficial invertebrates (see link below) likely to be present in the crop.