Graziers throughout the region may already be suffering under the weight of insect pressure, as reports increase of failing pasture growth on properties that support beef and sheep production.
Large tracts of country across hundreds of square kilometres remain bare according to local accounts, despite solid summer rainfall delivering adequate moisture to some paddocks in recent months.
While falls have been described as “patchy”, according to district rainfall records it’s the closest the north-west region has come to a normal wet season in years.
The positive turn in seasonal fortunes is compounding the mystery that surrounds the stunted pasture growth, with no scientific study yet to determine the exact cause.
Some graziers have taken to social media to question the connection to successive droughts, followed by the deluge of 2019 that swamped paddocks and drowned more than 500,000 head of cattle in one of the nation’s worst natural disasters on record.
Flinders Shire Mayor and grazier Jane McNamara is watching the creeping disaster unfold on her 14,000-hectare property, south of Hughenden.
“We’ve got one paddock where we’ve had probably around 200 millimetres, and you would expect to see some response,” McNamara told local ABC radio.
“The main response is a little bit under dead prickle trees and along the creek where there’s been a flood. Other than that, there’s really not a lot of response at all.
“It’s not just the grasses — it’s the weeds as well.”
McNamara has consulted with Department of Agriculture and Fisheries (DAF) staff in Longreach to conduct on-site tests to determine the cause of the pasture’s poor response.
She has so far been given no confirmation if her request will be approved.
In the interim she has spoken to InQueensland, calling for an urgent investigation and an escalation of resources that will unearth a conclusive explanation.
McNamara fears that further delays in combating the stalled pasture growth will lead to more producers de-stocking across the district, because they will be unable to feed their livestock on natural grass.
A spokesperson from DAF’s head office in Brisbane said investigations into the problem had been launched and were focusing on the lasting impacts that flooding during the 2019 monsoon trough and on-going drought have had on pasture and soil health.
Scientific officers were also addressing the impact of grasshoppers, the spokesperson said.
“The department is working with graziers across the region to help address the issue of poor pasture response and will continue to work with industry to identify management options for the future,” they said.
“Affected producers are encouraged to report problems by phoning 13 25 23.”
Pinpointing the cause
While McNamara waits for answers, she has some theories of her own as to what might be behind the region’s creeping pasture death.
“There’s a combination of factors at play, from prolonged drought, and not enough rain in some parts, but the problem is so widespread, those factors don’t account for all of it,” she said.
“It could be fungi, or it could be something that’s called the Mitchell grass flea, which sucks the life out of any stalk that manages to grow in these conditions.
“And because we’ve had such a long run of droughts, followed by insect infestations, the seed that needs to re-germinate has just been whittled away over time.”
Cloncurry and Julia Creek grazier Peter Hall has his doubts that floodwaters from 2019 might be to blame.
“I mean, it was very wet, but it wasn’t under water,” Hall told ABC radio.
“But any country that had that follow-up rain after that flood event it all grew grass.
“It’s just in 2020 it started acting a bit strange.”
Researchers from the University of Queensland have fixed their attention on the minuscule pest white ground pearl, or Margarodes australis.
A project funded by the national beef industry’s R&D and marketing body, Meat & Livestock Australia, started in January to determine if the insects were consistently present across other pasture dieback sites across the state and what role they might be playing in the widespread devastation.
With findings not due until the project’s completion in 2024, the white ground pearl has not been definitely named as the primary culprit.
McNamara said some graziers were considering a comprehensive and coordinated Mitchell grass re-seeding program to bring sustainable life back to their black-soil paddocks.
However, she concedes Australian native grasshoppers are a wily and robust foe.
“These bloody grasshoppers can eat two and a half times their own bodyweight in plant matter every day,” she said.
“And we have millions of them, which doesn’t leave a lot for anything else.
“Last year we had some people we knew doing some excavating around Winton with a front-end loader and they told me that the grasshoppers were metres down in the soil, hibernating, waiting for the rains and the plants to come.
“They don’t die and they are absolutely relentless. And they are about 200 million years old, which means they are a bit like the crocodile, highly evolved to suit their environment and survive in extreme conditions.”
Even if efforts to bring the grasshoppers to heel are successful, a new exotic pest is lurking on the region’s doorstep.
The Central American fall armyworm moth, which breached Queensland’s biosecurity shield last year, is slowly eating its away across the country’s major cropping and pasture zones.
McNamara says the exotic pest is close by in the Atherton Tablelands. It will only be a matter of time before it plagues the north-west region if effective control methods are not identified and deployed.
“We’ve had reports of it in Richmond and Croydon,” she said. “I don’t even really want to talk about that. We’ve had a gutful of these grasshoppers.”
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