Mouse plague threatens Australian grain farmers in WA and SA
Consensus Summary
Australian grain farmers in Western Australia and South Australia are facing a severe mouse plague threat as numbers surge to plague proportions. CSIRO researcher Steve Henry warns that mouse populations exceeding 800 per hectare qualify as a plague, with WA reporting 3,000–4,000 burrows per hectare in Geraldton and southern wheatbelt regions, while SA’s Adelaide Plains see 100–600 mice per hectare. The rapid breeding cycle—female mice produce 6–10 offspring every 19–21 days—risks devastating crop losses, particularly during seeding. Farmers are urged to apply zinc phosphide baits immediately, but supply shortages and timing challenges complicate efforts. The plague follows years of drought and recent rain, a pattern historically linked to outbreaks. Economic damage from past plagues, like the $1 billion loss in 2020–21, underscores the stakes, with farmers already struggling with fuel and fertilizer costs amid global tensions.
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Key details reported by multiple sources:
- CSIRO defines a mouse plague as more than 800 mice per hectare
- Western Australia is reporting 3,000–4,000 mouse burrows per hectare in Geraldton and southern wheatbelt regions
- South Australia’s Adelaide Plains are experiencing 100–600 mice per hectare, with some sites at trap saturation (400–600 mice/ha)
- Female mice can breed from six weeks old, producing 6–10 babies every 19–21 days
- The 2020–21 mouse plague in eastern Australia caused an estimated $1 billion in damage
- Steve Henry, CSIRO researcher, warns mouse plagues occur every 4–5 years and follow dry years with rain
- Farmers are urged to apply zinc phosphide (ZP) baits at seeding time to control mouse populations
- Mouse plagues cause economic, social, and environmental damage, including crop destruction and disease risks
Points of Difference
Details reported by only one source:
- WA Farmers grains section president Mark Fowler states the issue is urgent and seeding is already underway, making baiting critical
- Agriculture Minister Julie Collins mentions farmers are also dealing with fuel and fertilizer shortages due to the Iran war
- Grain Producers Australia’s Andrew Weidemann requests access to higher-dose zinc phosphide (ZP) baits, noting ZP25 is insufficient
- Mouse activity in Victoria, New South Wales, and Queensland remains low according to the latest CSIRO forecast
- Matt Davey, a farmer on Yorke Peninsula, reports mice are the worst he’s seen in four or five years and notes increased moisture from recent rain
- Agronomist Nathaniel Lloyd from YP Ag reports increased sales of mouse controls and forward orders for bait due to rising mouse activity
- CSIRO’s March house mouse forecast projected high mouse activity in parts of South Australia
- Steve Henry mentions record-breaking rain after 20+ months of drought contributed to the mouse surge
- Davey family’s cat, Oreo, is helping manage mice inside their home
Contradictions
Conflicting information between sources:
- The Guardian states WA is using the term 'plague' for 3,000–4,000 burrows per hectare, while ABC does not explicitly confirm this term for WA but focuses on SA’s high numbers
- The Guardian reports WA’s Geraldton region is most affected, while ABC emphasizes SA’s Adelaide Plains and Yorke Peninsula as key hotspots
Source Articles
Mouse plague hits WA grain farmers as numbers surge in SA: ‘You literally can’t get away from them’
CSIRO researcher says there are reports of up to 4,000 mouse burrows per hectare in parts of Western Australia Get our breaking news email , free app or daily news podcast Grain growers are on high alert as mouse numbers in Western Australia reach plague proportions and numbers surge in South Australia. Steve Henry, who researches mice and their impact on the grain industry at CSIRO, says more than 800 mice per hectare is considered a plague. Continue reading...
Farmers fear potential mouse plague as CSIRO warns of high numbers
As if the cost of diesel and the lack of fertiliser were not enough, South Australia's farmers are also facing the prospect of a mouse plague.