The Australian Pesticides and Veterinary Medicines Authority approved an emergency permit on Monday to ramp up production of stronger mouse baits for grain farmers facing a spreading plague across Western and central Australia. The decision gives producers access to ZP50 bait as pressure rises in parts of Western Australia and South Australia.

Grain Producers Australia secured the national emergency permit after farmers in towns including Northampton, Mullewa and Ravensthorpe recorded more than 8000 mice per hectare in April. That is well above the level at which a plague is typically declared, set at 5000 mice per hectare. Producers have been using 25g/kg zinc phosphide bait, known as ZP25, but said it was not strong enough for the numbers they were seeing.

Andrew Weidemann said the standard bait had fallen short as mouse numbers climbed, warning that plagues can bring massive crop and financial losses and heavy psychological stress for farmers, their families and people living in affected areas. The permit is intended to boost bait production so grain growers can respond with a stronger option as crops emerge and the risk to young plants grows.

The issue has spread beyond Western Australia, with South Australia also affected. In a statement, APVMA chief executive Scott Hansen said the emergency permit had been approved in line with strong safety and environmental standards, and that the fast-tracking did not mean shortcuts in assessing the product or the way it would be used, including its possible effects on human health, wildlife and the environment.

Western Australia Agriculture Minister Jackie Jarvis said the decision would give landholders and communities a way forward to carry out effective mice control. She said the state government was also providing extra funding to local government for baits and clean-up measures to help ease the cost and stress of the outbreak. Cec McConnell said restricted access to high-strength baits would be a valuable addition to support control efforts, adding that mice control had been extremely challenging this season and that ZP50 would be another tool to help landholders get on top of the problem at a crucial time.

The immediate question is no longer whether the plague is real. It is whether the stronger bait can reach farmers fast enough to matter while the crop is still vulnerable.