Rupanyup farmer and Grain Producers Australia chairman Andrew Weidemann said in his entire farming career, he had never seen growers baiting for mice at this time of the year. 

“Mouse activity seems to be mostly north of Minyip and then in a line across to Nhill,” he said.

“There is also activity near Birchip and Pimpinio.

“Farmers are finding deadheads in wheat particularly, and mice are chewing down eight to 10 inches from the head to above the final node.

“There was also damage in canola during flowering.”

Mr Weidemann said it was distressing to see the high levels of mouse activity in the region.

“People are trying to bait to reduce numbers before harvest, because we are looking at having a reasonable finish this year,” he said.

“However, if there is plenty of grain around at harvest, it is concerning to think how quickly mice might build up again.”

CSIRO researcher Steve Henry said mouse numbers were higher than normal for this time of the year in the Wimmera.

“It’s unusual to have mouse issues at this time of the year, so farmers are having to bait again, which is an expenditure they don’t normally have to factor in,” he said.

“It’s also difficult to predict the yield loss the damage will cause, but it’s important that farmers remain vigilant and check their crops.”

Mr Henry was also worried that populations might continue to increase throughout summer. 

“If the conditions remain favourable through summer and into next autumn, it will be very concerning,” he said.

“Mice are burrow dwellers and when it gets hot, they can dig down deep.”

Mr Henry said in the Mallee last week, he visited a paddock and found mice burrowed 75 centimetres into the soil. “That far down it was still damp and cool,” he said.

Murra Warra farmer and Victorian Farmers Federation president David Jochinke said many growers in the region were using planes to spread mouse bait at the moment, which cost about $7 a hectare.

“We are encouraging everyone to have a look at their crops and check for mice, if they can,” he said.