Alert over Russian wheat aphid

With confirmed reports of the Russian Wheat Aphid in South Australia’s grain growing regions, industry commentators are understandably concerned about the devastating pest infiltrating Western Australian cropping areas.

Plant Health Australia has previously said if the aphids did enter Australia, it could cause yield losses of up to 75 per cent.

Latest reports are showing the aphids have been detected in 22 properties in South Australia, covering 1400 square kilometres.

The pest has now also been discovered on crops in Bordertown on the South Australia/Victoria border.

While there is yet to be any discovery of these aphids in wheat or barley crops in this State, growers and agronomists have been put on high alert, with the Department of Agriculture and Food WA calling on growers to remain vigilant in the fight to combat the exotic pest.

Previously, Australia was one of the only grain growing countries in the world to be considered free of Russian Wheat Aphid.

The Department of Agriculture and Food (WA) has immediately strengthened its biosecurity regulations on the importation into the State of cut flowers and foliage, and on-arrival biosecurity inspections in airports have been increased.

DAFWA has also reviewed its machinery import regulations to ensure they are strict enough to combat the threat of the aphids coming over the boarder on equipment.

According to DAFWA Chief Biosecurity Officer John van Schagen, the aphids did not live in harvested grain, and could only survive on green plant material.

He said market access to Australian grain was therefore not an issue.

“Grain itself is not a carrier, and also since this pest is found in most other grain producing nations, it is a production issue, and it will not halt exports,” he said.

Mr van Schagen said the Department had pulled together a response team that would implement a co-ordinate surveillance strategy across the wheatbelt.

DAFWA development officer Dusty Severtson said it was important to look for aphids, even before feeding damage symptoms occurred.

“This aphid pest looks similar to other cereal aphids but has two ‘tails’ and lacks the usual ‘excretion tubes or exhaust pipes’ (siphuncles) on the top of the rear end of the body compared to other cereal aphids.”

The aphid is approximately 2mm long and pale yellowish green.

Affected plants may show whitish, yellow and red leaf markings and rolled or curled leaves. Plants with low aphid numbers may not show any symptoms and leaves and leaf sheathes should be directly inspected on tillers.

“We encourage farmers and agronomists to look for discoloured cereal plants and examine them closely with a hand lens,” Mr Severtson said.

Grain Producers Australia Vice Chairman and Miling farmer Barry Large said he was heading across to South Australia later this week to attend a National Management Meeting on the issue and to assess the extent of the situation.

Mr Large said the Russian Wheat Aphid was one of the worst pests that could threaten the yield potential of Australia’s cereal crops, but he stopped short of calling the infestation a disaster.

“I think disaster is the wrong word to use here, we don’t want to create a hysteria out there, but yes, it is another issue growers have to face, but we will deal with it,” he said.

“We are relying on growers and their agronomists to carry out inspections and surveillance, and to report any sightings that may be suspicious to the Department.”

“At the moment, it’s a waiting game.”

But Mr Large said he was aware of wheat germplasm that was resistant to this pest.

“We may now have to fast track the breeding of wheat varieties containing this germplasm to protect the industry,” he said.

Mr Large said if the pests did arrive in Western Australia, certain pesticides would be effective.

“However, its important to speak with your agronomist to determine the most effective active ingredient and the application rate,” he said.

Growers who notice aphids or signs of crop damage, particularly in newly emerging crops or grassy weeds, should report this immediately to the Pest and Disease Information Service on 1800 084 881 and via DAFWA’s reporting apps or online portal.