Southern New South Wales grain growers are urged to continue being vigilant for mouse activity, with numbers reasonably high in some cropping areas across the state.
The Grains Research and Development Corporation (GRDC) invests in regular mice monitoring and recent reports indicate areas, which began the season with big stubble loads or grain left on the ground, have experienced significant mouse damage.
CSIRO researcher Steve Henry, who has been surveying mouse activity for the GRDC-investment project, warns that bringing even a small infestation through to spring could create massive problems for summer.
“We are seeing lots of damage in barley stubbles as these crops provided not only ample feed for mice, but also shelter,” he said.
“I have seen high numbers in rice stubbles at Coleambally and we have had reports of mouse damage in canola across the southern irrigation zone, in places like Deniliquin and Finley.
“In rice stubble in Coleambally they are literally running around under your feet, and I have heard of one grower with a wheat crop on raised beds, who has flooded between the beds to flush the mice out.”
Mr Henry said many growers had already implemented successful control programs, which had reduced mice numbers across several cropping regions of NSW.
But he said it was critical on-farm control programs continued through winter and he urged growers to keep monitoring mice numbers and be proactive about management.
“If you are still seeing mice towards the end of winter, you need to consider baiting to prevent carrying high numbers into spring,” he warned.
"To look for active burrows, I suggest growers walk about 30 metres in from the edge of the paddock and set a 100 metre (1 metre wide) transect through a crop, following the furrows.
“They should walk slowly along the transect scanning for evidence of mouse burrows, taking note of any burrow that looks active and recording the number of burrows per 100 metre transect, and then repeat across two or four transects.
“If there are more than two to three active burrows per 100 metres, then they have a mouse problem.”
Should growers find they need to apply a zinc phosphide baiting at the end of winter, Mr Henry recommends the following:
- Apply bait according to the label;
- Allow at least four to six weeks before re-application of baits to minimise the chance of bait aversion. This allows mice that have previously tried the bait to try it again and also targets new animals in the population that are susceptible to the bait;
- Bait over large areas. Encourage neighbours to bait at the same time if they also have a mouse problem. The larger the area treated, the lower the chance of re-invasion post treatment.
Mr Henry encouraged growers and advisers to report and map mouse presence, absence and level of activity using MouseAlert (www.mousealert.org.au) so others can see the scale and extent of localised mouse activity.
MouseAlert also provides access to fact sheets about mouse control and forecasts of the likelihood for future high levels of mouse activity in each grain-growing region.
“We need more producers using MouseAlert so that the project can deliver more accurate forecasts of regional changes in mouse numbers,” Mr Henry said.
The GRDC-investment into mouse monitoring is a collaboration project between Landcare Research (New Zealand), CSIRO Agriculture and Food and the Invasive Animals Cooperative Research Centre.