Russians reappear with force

Russians reappear with force

Cropping
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GRAINGROWERS are being urged to prepare for a potential Russian wheat aphid incursion in the coming weeks, as sightings of the damaging pest have risen significantly.

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GRAINGROWERS are being urged to prepare for a potential Russian wheat aphid incursion in the coming weeks, as sightings of the damaging pest have risen significantly.

RWA was anecdotally found for the first time this year in an early-sown wheat at Whyte Yarcowie, near Jamestown.

Ground Up Agronomy agronomist Michelle Bammann, based at Clare, made the discovery in May and said increased RWA activity had caught many growers "off guard".

"Growers were planning to not use a seed treatment this year because there had been low numbers in the past couple of seasons," she said.

"Luckily, many chose to not take the risk."

But despite using a seed treatment to protect against RWA, Ms Bammann encouraged growers to closely monitor activity as crops progress.

"Generally after about six weeks, the treatment will lose effectiveness and infection rates can increase quickly," she said.

"There is a possibility of an outbreak in spring if growers do not monitor for infection."

Despite limited RWA sightings in the South East and most of the Eyre Peninsula, Port Germein consultant Barry Mudge said his region was experiencing "significant" infestations.

"The Crystal Brook area has a very high level of activity - it would be slightly less when compared with 2017 and it was severe," he said.

But Mr Mudge said seed treatments were not being widely used by growers.

"There has been such low levels of activity in the past few seasons that many did not see it as crucial," he said.

Just 30 per cent of growers on the Yorke Peninsula have opted to apply a seed treatment this season, according to AW Vater & Co agronomist Zack Zweck, Kadina.

"Sightings have definitely risen in the past few weeks and I expect to find more in the coming weeks," he said.

"Coastal areas seem to be hardest hit - early-sown crops with mild temperatures would have given the aphids a good start."

But Mr Zweck said populations had begun to move inland to more suitable conditions.

"Crops are up and away and paddocks have become perfect hosts for it to thrive," he said.

"The numbers are not horrendous, but if it keeps rising, growers will have to pull the trigger and spray."

RWA has also spread to the Riverland, but Pinion Advisory agronomist Richard Saunders, Loxton, said populations were suppressed with pest management.

"We have seen evidence of RWA and the distinct stripe on the leaves, so we can see where they have been," he said.

"But we have not found any large outbreaks.

"We were expecting greater numbers from a good green bridge in summer."

RELATED READING: Cropping fortunes vary across SA after dry June

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