Aphid biotype revealed
Australian scientists have confirmed the Russian wheat aphid, now established throughout parts of the nation’s south-eastern cropping regions, is a single biotype.
This new knowledge, achieved through research investments by the Grains Research and Development Corporation, will underpin ongoing and future research efforts aimed at combating the cereal crop pest first detected in South Australia in 2016.
Now present in areas of South Australia, Victoria, Tasmania and southern New South Wales, Russian wheat aphid has been the focus of GRDC research, which is providing the Australian grains industry with greater understanding of the pest and its potential impact.
Entomologists Maarten van Helden and Greg Baker from the South Australian Research and Development Institute have led experiments to identify the biotype of the aphid in Australia and possible origin of the incursion.
Their work has concluded the aphids in Australia belong to a single biotype, or have the same genetic make-up, named RWAAU1.
Dr van Helden said the virulence profile of RWAAU1 was almost identical to the American RWA1 biotype, which suggested the origin of the incursion in Australia was either from the United States or from the same origin as the original RWA1 first detected in Colorado in the States in 1986.
“Not only does this information help to identify the most likely geographical origin of the aphid, and the possible incursion pathway, but it also enables identification of the plant resistance genes – among the many existing overseas – that could be used by breeders to develop new resistant cereal varieties,” Dr van Helden said.
“While it is still important to know where, when and how this aphid has arrived in Australia to avoid other incursions, it is even more important to know what aphid biotypes have appeared in Australia, to be able to potentially develop sustainable management strategies, which include plant resistance as one tool.”
In addition to experiments to determine aphid biotype, the GRDC has been investing in research to confirm susceptibility of commercial wheat and barley cultivars to Russian wheat aphid; assessing potential sources of plant resistance; Russian wheat aphid biology, ecology and economic thresholds under Australian conditions; an investigation into alternate hosts for Russian wheat aphid; trials looking at insecticide efficacy; and development of practical resources.
INSIGHT: Experiments to identify the biotype of the aphid present in Australia and possible origin of the incursion have been led by SARDI entomologists Maarten van Helden, pictured, and Greg Baker.