One Mid West shire is handing out free baits to locals to help them cope with the region’s mouse plague amid calls for a stronger poison to be approved.
Farmers and suppliers have been pleading for higher-strength mouse bait ZP-50 to be approved for use long before the mouse epidemic hit farms and homes across the Mid West.
Calls for emergency permits have been denied, and farmers have been left out of pocket and with eaten seeds at a crucial time in their cropping season.
Cameron Beeck, general manager for agricultural chemical company 4 Farmers, said conditions were ripe for mice on the back of an excellent season and with major weather event. His company applied for an emergency permit for long-term 50-strength mouse bait in February.
Dr Beeck estimated there were “8000 mice per square hectare, trying to eat little seedlings.”
He said he knew looking for a long-term 50-strength mouse bait was going to be a long process.
The legal limit for zinc phosphide is 25 grams per kilo for farmers, although back in 2022, the Australian Pesticides and Veterinary Medicine Authority approved permits to Grain Producers Australia due to the mouse plague at the time.
“The 25g per kilo zinc phosphide works for normal pressures of mice, it doesn’t work when you have a mouse plague,” Dr Beeck said.
He believed that 95 per cent of WA growers had already started their seeding, and it was going to be an expensive process to get rid of the plague with the current limit of ZP25.
With his applications for ZP50 stretching back to February and continuously getting denied, he says he is seeing farmers struggle.
“You’re going to need to do more passes with 25, and that’s a very inefficient use of fuel that is scarce and expensive. It’s also inefficient use of what it takes to make the zinc phosphide,” Dr Beeck said.
Residents in the Shire of Morawa now have free mouse baits available for residential collection. Shire president Karen Chappel said that the move was “something the community has all welcomed”.
By the first day of collection last Wednesday, half of the mouse baits were gone, and by Friday last week, they needed to order more.
Cr Chappel was remaining positive about the mouse plague.
“The farmers are baiting, and if everyone else is baiting, we may win the war,” she said.
CSIRO research officer Steve Henry has researched mice for many years now and back in 2020, when farmers were saying that the bait did not work the way that they thought it should, he was part of the investigation.
He found “that mice were half as sensitive to the toxin as had been reported back in the 1980s and then, in fact, it required two milligrams of zinc phosphide to kill an average 15-gram mouse instead of one milligram that had been reported.”
Having completed field studies, the results showed “that the higher rate of bait works more consistently and more effectively than the lower rate bait.”
“Zinc phosphide, which is the product that farmers are allowed to use, the issues associated with secondary poisoning ... are actually quite low,” Mr Henry said.
Mr Henry explained how it was “about spreading the bait when other food in the system is at its lowest possible level.”
Jarrod Spencer, co-owner of Yandanooka farm, near Mingenew, has been “baiting probably for four or five weeks consistently.”
When the Midwest Times spoke to him last Wednesday, that morning his father had picked up 187 mice from their farm.
Mr Spencer has roped in his kids to help deal with the mouse problem, promising them “50 cents a mouse, which I think I should drop the rate a bit because we’re getting so many”.
He explained that due to the successful season last year “there’s going to be plenty of food on the ground” for mice.
An APVMA spokesperson said: “The APVMA has received applications for emergency use permits for a higher-strength zinc phosphide product and is prioritising those assessments.
“Any decision will be based on a rigorous scientific assessment of safety, efficacy and trade, including consideration of impacts on human health, animals and the environment.”
Dr Beeck added: “As soon as we get the green light, we’re ready to go.”
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