South Australian Research and Development Institute pastures scientist Alan Humphries has this year noticed more blue-green aphid damage to lucerne seedlings than normal.

The damage has occurred on a range of lucerne cultivars and has included plant death, which is not usually observed.

Mr Humphries would like to hear from anyone who has observed more than the usual damage.

SARDI scientists are monitoring the situation and feedback will help to determine whether further investigation is required.

Mr Humphries can be contacted with photos or descriptions of damage via email alan.humphries@sa.gov.au or phone (08) 8388 7198.

According to PestFacts South-Eastern and PestFacts SA and Western Victoria, services provided by the National Invertebrate Pest Initiative and supported by growers and the Australian Government through the Grains Research and Development Corporation (GRDC), blue-green aphids measure 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 blue-green aphids.

PestFacts coordinators say that 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 likely to be present in the crop.