Russian Wheat Aphids (RWA) have been discovered on a crop at Coonabarabran just two years after first being detected in South Australia.
The discovery has prompted the the Grains Research and Development Corporation (GRDC) to release a podcast offering grain growers and advisers insight into the identification, behaviour and management of the pest.
The symptoms of RWA are generally easier to spot than the insects themselves, with the sap sucking aphids introducing a toxin to the plants that causes leaf rolling, pale or purple lengthwise streaks, and stunting.
While this could be the last thing that NSW grain producers need at the moment the Tamworth Agricultural Institute professional officer Brett Lobsey said there is no cause for great alarm just yet.
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“The aphids are a-sexual so can be prolific and really nail crops if they get going,” he said.
“This is just one more thing that we need to be vigilant about and mindful of with cropping – it really becomes a global effort to monitor and fight.”
While beneficial insects, predatory beetles, hover flies and other species, including parasitic wasps, can exert effective biological control over the aphid, as well as insecticides, Mr Lobsey said that there are “some quality resistant material in the pipeline.”
“Prevention is better than a cure so producers can spray before aphids are present, although that raises ethical and financial issues,” he said.
“It is possible to make potentially resistant strains of wheat and other grains, but a lot of them are still in the breeding programs and probably just a few years from being available to buy.”
Aphids like to secrete themselves under the hoods of grain heads, so some strains are being bred that have smaller hoods to prevent this, while some strains have been genetically modified to include a DNA component that is toxic to the insect.
“Once again these things can raise ethical issues - we just need to be vigilant.”
