Growing numbers of mice are spreading across Western Australia's grain belt, damaging valuable crops that have been forecast to produce a record harvest this season.
Damage by rodents has been reported across a 400-kilometre stretch from Ajana on the northern tip of the grain belt to Dalwallinu in the central Wheatbelt.
Grains Industry Association of WA crop report author Michael Lamond said that, as the weather warmed up, he expected mice to spread further south, covering the entire grain belt.
"Mice are shaping up to be a problem," Mr Lamond said.
While not at the levels being seen in the eastern states, Mr Lamond said mice could eat through some of what had been predicted to be a bumper, 20-million-tonne harvest in Western Australia.
He said mice also posed a serious challenge for storing grain on farms during harvest time.
Long wait for baits
Growers eager to bait have been restricted by a four-week wait for supplies, boggy paddocks and a shortage of aviation companies to spread baits from the air.
For the first time, Marchagee farmer Michael O'Callaghan will bait his property in a bid to stop mice eating the forming canola pods.
With the chew cards used to identify the presence of mice on his Wheatbelt property completely consumed, Mr O'Callaghan chose to spend money spreading baits from the air.
"Every decision is hard when you are spending a lot of money, so it is not easy, and I don't want to do it, but I think it is the right decision," he said.
Harvest time providing more mouse feed
Elders agronomist Peter Elliot Lockhart said mouse numbers would continue building over the next few months during harvest time.
"There will probably be a bit of grain coming out the back of machines. There will be a bit of grain spilt around the place," he said.
"We don't have as much water available, so … they are not going to get that bad, but I suspect they will still be a problem for next season."
