GROWERS in areas where mouse numbers are at moderate levels have been advised to prioritise minimising grain on the ground after harvest to help reduce the potential for an outbreak ahead of sowing in 2023.
With Grain Industry Western Australia's (GIWA) October crop report predicting harvest yields close to last year's record-breaking figure of 24 million tonnes, it is likely that availability of food and shelter for mice will again be high in paddocks this year.
Pest experts undertaking research with investment from the Grains Research and Development Corporation (GRDC) are encouraging growers to harvest as cleanly as possible and practice good farm hygiene, especially around grain storage facilities, to reduce the availability of food.
Leading mouse researcher Steve Henry, from CSIRO, said food resources left in paddocks after harvest could sustain mouse breeding over summer and lead to higher mouse numbers when next year's winter crops are sown.
"Yields are likely to be high for many growers in WA this year which means the likelihood of grain being left on the ground is also high," Mr Henry said.
The recommendation was for growers to undertake a clean harvest by taking the time to ensure the header is set up properly, not just at the start of harvest, but also when changing crops and paddocks.
"Measure what's coming out of the front and back of the machine," Mr Henry said.
"The less there is, the less food for mice and the more chance they will take-up bait before sowing next season if populations are still a concern.
"And if you can avoid losing that grain, you are putting more grain in the header bin and money in your pocket."
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Research conducted by Grower Group Alliance (GGA), as part of a GRDC investment, determined more than $300 million worth of grain was likely left in paddocks last season from machine losses across all crops grown in WA.
Mr Henry said it was important to remember that each mouse consumed about three grams of food per day.
"Even if you think your paddocks are clean, remember only 150 kilograms per hectare of alternative food across your paddock equates to 50,000 mouse days of food," he said
"Also consider post-harvest stubble management like grazing and be proactive in spraying-out summer germinations.
"Any steps to reduce mouse food in the system helps to reduce mouse numbers over summer and minimise the risk for any potential mouse damage at sowing next season."
Growers also need to be aware of the 14-day withholding period before harvest as it may not be possible for them to bait in crops before harvest because of restrictions with label conditions.
The latest monitoring undertaken by Farmanco Management Consultants, Great Northern Rural Services and Ravensthorpe Agricultural Initiative (RAIN) through GRDC investments indicated mouse numbers in WA have been higher than usual across all port zones this year.
