Australia’s government said it was worried about the infestation’s impact on food supply, with Energy Minister Chris Bowen saying officials were concerned about the mice situation, including in Western Australia. Bowen said the government would keep working with industry to reduce the effect on domestic and export food supplies.
The concern comes as Australia, one of the world’s largest wheat exporters, enters a narrow seeding window across major grain districts. Farmers say mice are digging along seed rows, eating freshly sown grain and raising the risk that some crops may fail before they properly emerge.
Australia mouse plague reaches a critical point for grain growers
In Western Australia, the outbreak has been reported across parts of the northern grain belt, around Geraldton and through sections of the Wheatbelt. CSIRO researcher Steve Henry told The Guardian that more than 800 mice per hectare is considered plague level, with some WA reports reaching 3,000 to 4,000 burrows per hectare.
South Australia is also under pressure. ABC Rural reported that CSIRO researchers were trapping hundreds of mice on the Adelaide Plains, while growers on the Yorke Peninsula and other cropping areas were preparing to bait as they sowed crops.
The timing is especially damaging because the early crop-establishment phase can determine final yields. If mice eat enough seed before germination, growers may face costly re-sowing, thinner plant stands or reduced production later in the season.
Stronger bait requests add urgency to Australia mouse plague response
Growers are pressing for stronger zinc phosphide bait, arguing that current products are less effective when paddocks contain large amounts of alternative food. Grain Central reported that the Australian Pesticides and Veterinary Medicines Authority had received applications for higher-strength ZP50 bait and was prioritising its assessment.
The bait debate has become a flashpoint because seeding is already underway. Farmers say a delayed decision could leave them fighting a larger population once crops are established and mice have more cover.
The Grains Research and Development Corporation urged growers to inspect paddocks closely for mouse activity, noting that high stubble loads can hide signs of infestation and that food left from previous crops can accelerate population growth.
Past outbreaks show how quickly losses can spread
The 2026 outbreak is reviving memories of the 2020-21 mouse plague across eastern Australia. In May 2021, Reuters reported that heavy rain after drought helped produce a bumper grain crop and abundant food for mice, fueling a rapid breeding cycle that devastated farms.
The damage did not end with crops. Later that year, The Guardian reported that mouse burrows had weakened levees in flood-hit New South Wales, adding infrastructure problems to grain contamination, machinery damage and household stress.
Those earlier outbreaks show why farmers are treating the WA and SA surge as more than a seasonal pest problem. A severe mouse plague can move from paddocks into storage sites, homes, livestock feed and transport systems, increasing costs even after the first wave of crop damage.
Food supply risk depends on speed of control
For now, officials have not declared a national shortage. The immediate threat is to crop establishment and farm margins, especially in districts where mice are already above plague thresholds. But if control efforts fail during seeding, the damage could flow through to grain volumes, export planning and food supply confidence.
Farm groups are urging rapid monitoring, bait access and coordinated reporting so regulators can assess the scale of the outbreak. With mouse numbers capable of increasing quickly, the next few weeks may decide whether the infestation remains a regional farm emergency or becomes a broader supply-chain problem.
