Monitor paddocks to prevent losses from mice

Author: Natalie Lee | Date: 06 Sep 2012

mouse hole

Western Australian grain growers are urged to inspect individual paddocks for mice in coming weeks, as the pests have the potential to go unnoticed and cause significant yield losses in developing crops.

“Some farmers believe mice will not pose a risk to crops if they have baited once, or mouse activity earlier in the season wasn’t high, but spring is a critical period for mouse activity and possible damage,” Grains Research and Development Corporation (GRDC) WA regional program manager Darren Hughes said.

“Mouse numbers can build and decline rapidly, and carry-over populations of mice from autumn have the potential to cause severe damage to crops at the flowering and seed set stages.”

Information about mouse management is available in a just released GRDC Mouse Management fact sheet aimed specifically at WA growers and endorsed by the National Mouse Management Working Group (NMMWG)*.

The fact sheet includes information on monitoring; crop damage; control; economic thresholds; ongoing management and hygiene; and useful resources.

Dr Hughes said mouse activity had been reported in pockets throughout the WA grainbelt in recent weeks, including in the Northern Agricultural Region, the central grainbelt and the Esperance region.

Higher-than-usual mouse numbers were also recorded in many areas in WA in autumn.

Paddocks not harvested last summer due to unseasonal rains appeared to be particularly affected.

Dr Hughes said mouse numbers observed around grain storages were not a reliable indication of paddock populations.

“Therefore it is important to monitor for mice on a paddock-by-paddock basis, as is common practice for monitoring for insects,” he said.

“Hygiene and ongoing management are important to reduce mouse numbers and their carry-over between seasons, but baiting is the only option for in-crop control once mice have reached damaging levels.

“In a cereal crop estimated to average 1.2 tonnes per hectare, 5 per cent damage will cause an income reduction of about $15/ha.

“Ground application of zinc phosphide bait at 1kg/ha costs less than that amount but varies depending on retail bait prices and the application method.

Mouse hole

Regular monitoring and stringent
control measures are necessary to
prevent crop losses from mice.

“Monitor crops about seven days after baiting to check for invading mice from adjacent areas; rebaiting may be necessary.”

Dr Hughes said gloves should always be worn when handling mice as they carried disease.

Mouse damage and activity in WA can be reported to the GRDC-supported Department of Agriculture and Food WA PestFax service, with reports mapped on PestFax Map and included in the PestFax newsletter.

To sign up for the PestFax newsletter or to report sightings email, or use the new online reporting capability available by clicking on the ‘PestFax report form’ link next to the map at

The GRDC Mouse Management fact sheet is available at and is included in the September/October edition of the GRDC magazine Ground Cover, which has recently been mailed to growers.

Growers can also seek advice from their agronomist, S7-Chemcert registered mouse bait retailers or their regional DAFWA office.

* The NMMWG includes representation from relevant state governments, the Australian Pesticides and Veterinary Medicines Authority (APVMA), the Department of Agriculture, Fisheries and Forestry (DAFF), the GRDC and the Invasive Animals CRC. The group also involves grains industry stakeholders and grower organisations.


PHOTO CAPTION: Regular monitoring and stringent control measures are necessary to prevent crop losses from mice.


Natalie Lee, Cox Inall Communications
08 9864 2034
0427 189 827

GRDC Project Code IAC00001

Region West, North, South, National