The APVMA is completely tardy and irresponsible in their delay
Across the grain belt of Western Australia and South Australia, a slow-moving regulatory process finally yielded to the weight of a living crisis: months of unchecked mouse plagues consuming crops, invading homes, and eroding the patience of rural communities. Australia's chemical regulator, the APVMA, has approved a double-strength zinc phosphide bait—a measure backed by CSIRO science but long delayed—offering farmers a more effective tool against infestations reaching 8,000 rodents per hectare. The approval arrives as a kind of institutional reckoning, a reminder that the pace of bureaucracy and the pace of nature are rarely in agreement, and that the cost of that gap is borne by those closest to the land.
- Mouse populations of up to 8,000 per hectare have been consuming seeds before germination, collapsing paddock soil into warrens, and pushing into homes where they chew cables and cushions in what residents call the worst plague on record.
- Rural leaders grew openly furious with the APVMA, accusing the regulator of being 'completely tardy and irresponsible' and of placing wildlife concerns above the welfare of farming communities enduring months of property damage and psychological strain.
- The APVMA had previously rejected applications for the stronger 50g/kg bait, citing insufficient research quality—even as CSIRO published four peer-reviewed papers confirming the double-strength formula outperforms the standard 25g/kg version.
- Emergency approval has now been conditionally granted, but farmers must complete accreditation training before they can purchase the stronger bait, adding one more procedural step between crisis and relief.
- Scientists are continuing to monitor secondary poisoning risks to non-target wildlife, with current research suggesting no increased danger from the stronger formulation—though the winter grain crop's fate still hangs in the balance.
In the grain belt of Western Australia, farmers spent months watching mice devour their crops before seeds could even germinate. The ground across paddocks collapsed into a maze of burrows, and the rodents moved beyond fields into homes—chewing refrigerator cables, destroying furniture, overwhelming communities that described it as the worst mouse plague on record. CSIRO researchers estimated 8,000 mice per hectare in parts of WA's northern grain belt.
For months, the Australian Pesticides and Veterinary Medicines Authority had resisted calls to approve a double-strength zinc phosphide bait—50 grams per kilogram versus the standard 25-gram formulation—citing concerns about research quality. But CSIRO had published four peer-reviewed papers confirming the stronger bait was more effective, and the grain industry had been lobbying hard for emergency access. Local leaders grew openly hostile toward the regulator, with Morawa Shire President Karen Chappel accusing the APVMA of being 'completely tardy and irresponsible.'
The approval finally came in May, bringing relief to farmers like Scott Bridgeman in Northampton, who said it would help him sleep at night. Grain Producers Australia welcomed the decision, though it came with conditions: farmers must complete accreditation training before purchasing the stronger bait. For residents like Erika Brown, who had been relying on bucket-and-cage traps and watching even her chickens fail to keep pace with the infestation, the approval marked the end of a long and exhausting wait.
Scientists stressed that the stronger formulation showed no increased risk of secondary poisoning to wildlife so far, though monitoring continues. Whether the approval arrived in time to protect the winter grain crop remains uncertain—but after months of regulatory delay, the machinery had at last begun to move.
In the grain belt of Western Australia, farmers have spent months watching mice destroy their crops before the seeds even had a chance to sprout. The rodents burrowed through paddocks with such intensity that the ground itself seemed to collapse beneath them—holes everywhere, dirt scattered like the work of a thousand small excavators. By May, the Australian Pesticides and Veterinary Medicines Authority finally approved what farmers had been asking for: a stronger poison.
The APVMA conditionally allowed the manufacture and sale of mouse bait containing 50 grams per kilogram of zinc phosphide, double the standard 25-gram formulation that had proven inadequate against the scale of the infestation. The decision came after months of delay that left rural communities frustrated and, in some cases, angry. A CSIRO study earlier in the year had estimated 8,000 mice per hectare in parts of WA's northern grain belt. The creatures had moved beyond the paddocks into homes and sheds, eating cables from refrigerators, chewing cushions, and creating what residents described as the worst mouse plague on record.
Scott Bridgeman, a grain farmer at Northampton in WA's Midwest, said the stronger bait would help him sleep better at night. He had watched mice destroy his paddocks where he wasn't running livestock, leaving behind a warren of holes and displaced earth. At a rural retail store in Northampton, the manager was ordering 100 mouse traps at a time and still couldn't keep up with demand. Farmers were driving around at night, he said, killing hundreds and thousands of mice—and those were just the ones they could see.
The frustration with the regulator's pace had become sharp. Morawa Shire President Karen Chappel said the APVMA had been "completely tardy and irresponsible" in its delay, and accused the agency of prioritizing wildlife over human life. The grain industry, through Grain Producers Australia, had been lobbying for the emergency permit for months. When it finally came through, Andrew Weidemann of the GPA called it a relief, though he acknowledged the approval came with conditions: farmers would need to be trained and accredited before they could purchase the stronger bait.
The path to approval had been longer than it should have been. The APVMA had previously rejected applications for the higher-potency bait, saying the research provided was "not of sufficient regulatory quality." But the CSIRO had published four peer-reviewed papers examining zinc phosphide efficacy, all of which found that the 50-gram rate was more effective than the 25-gram version at controlling mice. Steve Henry, a CSIRO research officer who co-authored the papers, said the studies confirmed what farmers had been telling scientists all along: the weaker bait simply didn't work consistently.
For residents like Erika Brown in Northampton, the approval came after months of living with an infestation she described as disgusting, filthy, and horrific. She had been relying on bucket-and-cage traps because she preferred not to use poisons on her property. Even her chickens couldn't keep up with the mice. The APVMA's approval included specific-use instructions and controls designed to minimize exposure to non-target animals and reduce risks to wildlife and the environment. Scientists, including Henry, said there was no indication so far that the stronger zinc phosphide increased the risk of secondary poisoning in birds, though research was continuing.
Farmers needing accreditation could find training information through the Grain Producers Australia website. The national emergency permit was designed to be flexible, helping those with moderate or high mouse activity—identified through a national monitoring network—to access the stronger bait. After months of waiting, the regulatory machinery had finally moved. Whether it would move fast enough to save the winter grain crop remained to be seen.
Citas Notables
The APVMA is completely tardy and irresponsible in their delay in responding to the request to have this bait increased to 50 grams of zinc phosphide.— Karen Chappel, Morawa Shire President
All four studies have shown exactly what farmers were telling us, that the 25g/kg bait doesn't work consistently.— Steve Henry, CSIRO research officer
La Conversación del Hearth Otra perspectiva de la historia
Why did it take so long for the regulator to approve something the science already supported?
The APVMA said the earlier research wasn't of sufficient regulatory quality, but the CSIRO had published four peer-reviewed papers showing the stronger bait worked better. It's a gap between what scientists know and what regulators feel confident enough to act on—and in this case, that gap cost farmers months.
What does 8,000 mice per hectare actually look like on the ground?
It looks like a landscape that's been hollowed out. Holes everywhere, dirt piled up, seeds eaten before they germinate. One farmer described it like a rabbit warren. The mice were so numerous that farmers were killing hundreds and thousands in a single night.
Why couldn't the weaker bait just be used in higher quantities?
That's not how it works. The bait is a fixed formulation—you can't just use more of the weaker version and get the same effect. You need the poison concentration itself to be stronger to kill the mice reliably, especially at these population densities.
What's the risk with the stronger bait?
The main concern is secondary poisoning—birds eating poisoned mice and getting sick themselves. The CSIRO hasn't found evidence of that happening yet, but they're still studying it. That's why the approval came with specific conditions about how and where farmers can use it.
So farmers still have to wait for training before they can buy it?
Yes. The permit requires accreditation. It's a safety measure, but it also means there's another step between approval and actual use. For farmers who've been dealing with this for months, that's another delay, even if it's a shorter one.
What does this say about how Australia handles agricultural emergencies?
It shows the tension between caution and urgency. The regulator was being careful, but rural communities felt abandoned. A shire president said the APVMA was prioritizing wildlife over human life. That anger reflects how long people had to live with something they felt was preventable.