Did you know we recently detected insecticide resistance in some bluegreen aphid populations?
While the evolution of insecticide resistance is common in some species of crop pests, such as the green peach aphid, the resistance we have just discovered in bluegreen aphid appears to be the first for this species.
Now with a new investment, we are gathering key information on these resistant strains of bluegreen aphid.
What is a bluegreen aphid?
The bluegreen aphid (Acyrthosiphon kondoi) is a pest of lucerne, lupins, medics, clovers, and pastures. This tiny pest feeds directly on the foliage, damaging the plant and spreading harmful viruses through infected crops.
The bluegreen aphid is grey-green to blue-green in colour and can be confused with the pea aphid or the green peach aphid.
Most common in spring but also active in autumn and winter, they are widely distributed and found in all states of Australia.
For more information on the identification and biology of bluegreen aphid see our PestNote.
First of its kind insecticide resistance
Historically, growers have protected their crops from bluegreen aphid by spraying insecticides that efficiently control these aphids.
However, our recent research revealed some bluegreen aphid populations in South Australia and NSW have newly evolved resistance to the organophosphates and carbamates registered and routinely used to control them.
This resistance in bluegreen aphid appears to be the first of its kind in this species and questions remain about how industry can best tackle this evolutionary event.
New research underway
Cesar Australia and Lucerne Australia have commenced a new project, with investment from the GRDC and AgriFutures Australia, to help growers manage insecticide-resistant bluegreen aphid. As part of the project, we are gathering key information on resistant strains of bluegreen aphid, including where they have spread, what crop types they are most common in, and whether resistance is increasing in the populations over time.
For our project to deliver the best outcome for growers, we need your help!
If you, or someone in your area, has experienced any issues with bluegreen aphid, we request samples of the aphids be posted to Cesar Australia’s laboratories for resistance testing.
Your help will allow Cesar Australia and Lucerne Australia to provide regional and seasonal recommendations (e.g., which chemicals are most effective) for bluegreen aphid control and help prevent future resistance (e.g., to new chemicals) arising in coming years.
For information on collecting and posting samples, please contact Dr Evatt Chirgwin (email: echirgwin@cesaraustralia.com or phone: 0487292556).
Bluegreen aphid management
The rise in insecticide resistance in bluegreen aphid means extra consideration needs to be given to how this pest is managed. While our current project is exploring sustainable long-term management solutions, there are already established management practices that can help in the short term.
Regular monitoring is needed for vulnerable crops during bud formation to late flowering.
Natural enemies, including ladybird beetles, parasitoid wasps, hoverflies, and lacewings, can be very effective at supressing aphid populations.
It is also possible to reduce damage by selecting cultivars that are more resistant to aphid feeding damage and controlling weeds around crops during summer and early autumn to remove alternate bluegreen aphid hosts between growing seasons.
If chemical options are required, avoid spraying with organophosphates & carbamates. If needed, Flonicamid (MainMan) has an emergency permit approved for use on bluegreen aphid in lucerne seed crops and sulfoxaflor (Transform) is registered for use on bluegreen aphid in some pulses.
Cover image: Photo by Andrew Weeks, Cesar Australia
