Australian farmers in South Australia and Western Australia have been granted temporary access to a stronger mouse bait, ZP50, following unprecedented mouse plagues across the grain belt. The Australian Pesticides and Veterinary Medicines Authority (APVMA) issued an emergency permit for the 50g/kg zinc phosphide bait, doubling the strength of the previously available ZP25. Grain Producers Australia (GPA), which applied for the permit, said the move was vital to mitigate crop and financial losses, as current infestations reach up to 4,000 mice per hectare in some areas. CSIRO research indicates that numbers above 200 per hectare already impact crops, with plagues defined at 800 to 1,000 mice per hectare. CSIRO expert Steve Henry noted the situation is worsening and advised urgent bait application. While the permit is temporary and further studies on environmental impact are ongoing, no bird deaths have been observed so far. Farmers are encouraged to follow safety guidelines closely, particularly due to the high reproductive rate of mice, which can rapidly increase populations. The emergency measure comes amid broader agricultural pressures, including rising fuel and fertiliser costs, low rainfall, and the potential impact of a 'super El Niño'. GPA is also offering training and information sessions for farmers to safely use the new bait.