AgroPages-Resistant varieties the key to aphid control-Agricultural news

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Developing aphid-¬resistant cereal varieties may be the only way to combat Russian wheat aphid in the long term.

The aphid, first found in South Australia in May, has been detected across Victoria including in the Wimmera and Mallee and as far east as near Echuca.

Victoria’s chief plant health officer Gabrielle Vivian-Smith said the idea of having aphid-resistant germplasm was “definitely the long-term option”.

“It’s a race in terms of breeding resistant germplasm that is also high-yielding,” Dr Vivian-Smith said.

“In national management terms we’ll be looking at how we work together to ensure there’s investment in that area.”

Agriculture Victoria rural recovery senior officer Darryl Pearl said he understood the Grains Research and Development Corporation had identified the aphid as a risk to Australia and had taken steps towards getting resistant plant material from South Africa, the US and Europe, into pre-breeding programs.

Mr Pearl said the losses from aphid attack could be as high as 80 per cent in barley and 70 per cent in wheat.

He said if summer temperatures reached 37C or higher, growers could expect 50 to 70 per cent of aphids to die.

“If the winter temperature gets to zero, then we can expect 50 per cent of the aphids to die, but they are used to low temperatures,” Mr Pearl said.

West Australian-based plant scientist associate professor Mehmet Cakir said the key to controlling the pest was to develop resistant varieties.

Dr Cakir said while the aphids could be controlled with insecticide to some extent, the aphid damage caused leaf rolling and the aphids hid inside the leaf, making herbicide ineffective. Dr Cakir called on the Federal Agriculture Minister Barnaby Joyce to reinstate funding to help breed resistant varieties.

Dr Vivian-Smith said growers should consider spraying if 20 per cent of seedlings were infested during the growth stage or 10 per cent infected after tillering.

“We really need to monitor it and keep an eye on the aphids becoming resistant to chemicals,” Dr Vivian-Smith said.

The Australian Pesticides and Veterinary Medicines Authority has issued two permits for emergency chemical or off-label use to control the Russian Wheat Aphid.

Agriculture Victoria statewide specialist chemicals Steve Field said grain growers had to be careful about grazing withholding periods and spraydrift when using the chemicals.