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Doubling down on mouse bait effectiveness with ZP50

GPA Southern Region Director Andrew Weidemann and CSIRO mouse expert Steve Henry tell Jack Cresswell what’s been happening behind the scenes to ensure farmers have access to the best tools for defending crops against one of our most damaging pests, mice.

Mice were a hot topic in 2021, when they ran riot throughout grain producing regions, especially in New South Wales and Queensland.

And after two high rainfall years and two big harvests across much of Australia, Steve warns 2023 “smells a lot like” previous mouse plague years, including 2010-11 and 2016.

“One of our concerns at the moment is there’s just simply so much vegetation in the system,” he said. “Farmers haven’t been able to get on their country; there’s lots of food around. It’s going to be really difficult to see what’s going on in those paddocks until crops are harvested or until we get some significant grazing pressure on those paddocks.”

Steve said lodged and hail damaged crops also had put a lot of food in the system for mice and after a mild summer “we really are quite concerned what might be happening as the autumn develops”.

He said the best time to be spreading mouse bait was at sowing, using a spreader hooked behind the seeder.

“You’re burying a lot of that residual food in the act of sowing the crop,” he said. “And at that point, you’re actually able to take mice out of the system by baiting them before they have a chance to discover your freshly sown crop and start to smash it. Because once they get switched on to those freshly sown rows, they’ll just go up the rows and pluck every seed out.”

Andrew said GPA had worked with APVMA to obtain an extension to its emergency permit for ZP50 mouse bait. Under the new rules, growers and contractors must undertake stewardship training and reporting through GPA Training. Data gathered will be used to support ongoing research and future applications for registration.

“This is going to be the largest .. trial work right across Australia, wherever mice are going to be prevalent in 2023,” he said. “We know that we’re probably on the cusp of another mouse plague. So let’s be ready to do it.”


  • Control summer weeds

  • Reduce available feed by grazing stubbles

  • Monitor how much grain is lost through the header

  • Walk paddocks to check for active burrows and put out chew cards

  • Be prepared to bait if you see activity

  • Use a lethal dose of mouse bait at the label rate of 1kg/ha


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