Farmers on locust alert

From the Eyre Peninsula to the Mid North and the South East, the pest has been reported at various locations, but the Australian Plague Locust Commission says the numbers are not concerning at this stage.

Since its inception more than 50 years ago, the APLC has surveyed the Flinders Ranges, North East Pastoral area, Riverland and Murraylands, but does not venture further south, according to director Chris Adriaansen.

Mr Adriaansen said this was due to the state nominating those areas initially and all other regions were covered by a state body - PIRSA.

He said the commission had received reports of locusts in the state and two small patches of locusts had been observed in the designated areas, but they were not extensive or in high density.

"There are numbers around but they're not in any great density that would cause any significant concern," Mr Adriaansen said.

"The level of pasture growth has been quite phenomenal due to increased rainfall and, in fact, in quite a few areas the pasture is actually too thick for locusts to be successful in them.

"Locusts are actually looking for and residing in areas where the pasture is not as thick.

"We've certainly had a number of reports further south and observed ourselves the locusts are probably a little bit more prevalent in areas of crop stubble than they are in areas adjacent areas of pasture - again, that's because of the density of the vegetation.

"They're certainly feeding, but they're also looking for areas that are a little bit clearer where they can get a bit more sunlight and get their body heat from exposure to the sun - most of the pasture areas have got a very high density of vegetation and aren't conducive to that."

In the Eyre Peninsula, locusts have been hitching a ride in the back of utes, according to Nutrien Ag Solutions Wudinna agronomic advisor Leigh Davis, with swarms visible across the region.

"A farmer actually hit a swarm on his way into the office and they hung around in the back of his ute," he said.

"I went out and identified them while he was here and they were definitely plague locusts.

"There are plenty in the paddocks at the moment as well - whether they are all locusts or some grasshoppers I can't say for sure, but they're out there."

Although he had not fully investigated the issue yet, Mr Davis said it was a hot topic among farmers in the region.

"Just about every farmer has noticed them - they're hard to miss when they're jumping right in front of you," he said.

"There's more than we would usually see - that could be attributable to the rain we've seen in the Upper Eyre Peninsula giving them a bit more feed to build up on.

"I would say in the last three or so weeks numbers have grown - I was out in the paddocks last month and there were a few smaller ones around but nothing like what we're seeing at the moment.

"I don't know if it will be something we need to be worried about too much or not yet, but it's something we're definitely keeping an eye on."

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Freeling farmer Corbin Schuster first noticed locusts in his paddocks in the last week and swiftly raised the issue with agronomists who reported similar numbers further north.

"It's been a reasonably dry summer for us, the rest of Australia has copped it but we haven't, so there hasn't been a whole lot of summer spraying going on and we haven't really had to go to the paddocks all that much," he said.

"We've been spreading a bit of poultry manure for fertiliser in a couple of paddocks north of Adelaide and there were more than enough locusts flying around to notice them.

"Once you get those really big rains in the northern part of the state, they build up there and then gradually fly down.

"We've had those rains and there now seems to be a good number of locusts getting around and it takes a couple generations of mature locusts and egg laying and all that kind of stuff to get to a plague, but starts small and probably doesn't take all that long to build up to a plague type of status.

"I mean, I'm not an entomologist and I don't know their exact lifespan or how long it takes them to reach maturity and lay eggs, but if it's like any normal insect one, one adult female can lay a hell of a lot of eggs and it can get out of hand pretty quickly - plagues just don't show up overnight."

With healthy grain prices on offer for croppers, Mr Schuster said he wanted to make sure he still had something left to sell without it being destroyed by locusts.

"It's something we haven't really had to deal with in plague numbers since about 2010 or 2011," he said.

"With the shortages of all the chemicals and shortages with fertiliser and the prices of everything, the last thing you want to do is have a massive demand for insecticides and find out there's not enough of them."

The commission is currently surveying the NSW and SA border and the eastern side of the Flinders Ranges after surveying as far north as Oodnadatta last week, which Mr Adriaansen said was being undertaken due to an improvement in rainfall and pasture growth.

"Prior to February, the habitat conditions weren't all that conducive to locusts and therefore there wasn't a real lot of pointing survey in those areas," he said.

"There are scattered locusts, but there's no high density infestations and there's no evidence of any larger population further afield that is likely to migrate into SA at this stage.

"The background population that's there at the moment, if the conditions remain favourable, then there is the potential for some level of breeding and expansion of the population but at this stage, it's not an issue or concern for SA."

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