Potential for mouse plague in SA this autumn

Author: Sharon Watt | Date: 17 Feb 2014


South Australian grain growers are being advised of the potential for a mouse plague this autumn.

Grain remaining on the ground after harvest and from barley crops damaged by wind before harvest is supporting population build-up, with growers reporting the emergence of fresh mouse holes over recent weeks.

While mice were not a major issue during the 2013 cropping season and numbers are not currently high, populations can rapidly build if food sources such as spilled grain are plentiful over the months after harvest.

Supported by the Grains Research and Development Corporation (GRDC), pest management authorities are urging growers to take steps to discourage a potential increase in mouse populations.

The National Mouse Management Working Group (NMMWG), which was set up with GRDC support in 2011 to co-ordinate actions to counter mouse plagues and to assist bait availability on-ground when needed, recently met in Adelaide to discuss the current situation.

Biosecurity SA research officer, Greg Mutze, who addressed the NMMWG meeting, says spilled grain in paddocks is the key that allows mouse numbers to build up rapidly and damage the following year’s crops.

Mr Mutze said an elevation in mouse populations usually occurred the year after a bumper harvest.

“The problem arises when a lot of grain is left on the ground – a small percentage of a large harvest can equate to a significant amount of feed for mice,” Mr Mutze said.

“Some areas also had bad wind damage that dropped a lot of grain before harvest – that is the worst possible scenario if combined with summer rains which promote weeds and mouse habitat.

“Managing weeds over summer to reduce mouse habitat and food sources is critical for areas with large grain losses, but even with the best management over summer it is likely that some baiting will be required at seeding.”

Other measures that can be taken to curb mouse breeding include:

  •      For those who are still running sheep, heavy grazing after harvest to help clean up harvest grain losses (ensure sufficient ground cover is left to minimise erosion potential).
  •      Cleaning up any concentrated spills of grain around field bins, augers, silo bags and other grain storage.
  •      Removing or reducing cover, including plant material, rubbish and general clutter around buildings, silos and fodder storage as these all provide protection for mice
  •      Rolling stubble in summer, which exposes mice to birds of prey. Knocking down or burning stubble in mid-autumn, after numbers have built up, appears to have little benefit.

Authorities say the best time to bait is either just before or after seeding. Baiting earlier in the year will be less effective, especially where an abundance of feed sources exists.

While supplies of commercial zinc phosphide bait are now readily available, the GRDC is working with peak industry body Grain Producers Australia to address access to bait supply should a plague eventuate.

Primary Industries and Regions SA (PIRSA), working with the Invasive Animals Cooperative Research Centre, is currently gathering information on the regional status of mouse populations and welcomes local reports from agronomists to build a state snapshot of distribution.

Meanwhile, through a new three-year GRDC-funded study, monitoring and modelling of mouse populations across the grain belt of Australia continues. The project is a collaboration between Landcare Research (New Zealand), CSIRO Ecosystem Sciences and the Invasive Animals CRC.

The aim of the project is to monitor mouse populations across grain growing areas and develop predictive models to forecast outbreaks. It will also disseminate the results of the monitoring and predictions to farmers and industry through the GRDC to improve awareness of and preparedness for increases in mouse activity. Information and outcomes will also be relayed to the NMMWG.

The GRDC is also funding the development and distribution of a mouse extension newsletter designed to keep SA agronomists up to date with population developments and recommendations for control of mice across SA.

Co-ordinated by agricultural consultant Allan Mayfield, the newsletter will be issued every month up until June this year. Anyone wishing to receive the newsletter, can contact Dr Mayfield on 0418 818569 or emailallan@asmayfield.com.au.

Further information on mouse monitoring and management is available viathe GRDC Fact Sheet, www.grdc.com.au/GRDC-FS-MouseControl.


Media Interviews

Greg Mutze, Biosecurity SA

08 8303 9505


Allan Mayfield, agricultural consultant

0418 818569


Sharon Watt, Porter Novelli 
0409 675100

Caption: Reducing mouse habitat and food sources is critical for areas with large grain losses.

GRDC Project Code IAC00001 and IAC00002

Region South, North, West, National