Significant numbers of mice present across regions of southern NSW suggests an early start to breeding, prompted in part by a warm and dry winter and last year’s high stubble load.
The Grains Research and Development Corporation invests in regular mouse monitoring and recent reports indicate areas, which began the season with big stubble loads or grain left on the ground, have experienced mouse damage.
CSIRO researcher Steve Henry, who has been surveying mouse activity for the GRDC-investment project, said a high stubble load, in some cases, masked signs of mouse activity.
‘‘The level of activity we are seeing now is higher than we have seen in the previous five years of monitoring, and suggests levels over winter were higher than realised,’’ Mr Henry said.
‘‘It can be quite deceiving for growers, because while we are seeing higher numbers than we would expect, particularly close to the Victorian border around Deniliquin, the damage levels are variable.
‘‘The damage is higher in canola and lupin crops, and we have higher numbers of mice in those crops, which had a preceding barley crop.’’
Mr Henry’s advice to growers is to continue vigilance in assessing mouse numbers and bait where there is evidence of high levels of activity or signs of crop damage.
‘‘While mice will cause some issues in mature crops by climbing stems and chewing nodes resulting in dropped heads, the bigger concern with numbers increasing is the potential impact of high numbers at sowing next autumn,’’ he said.
‘‘I have heard reports of significant areas of baiting already. By attempting to reduce numbers now, growers can potentially lower the rate of mouse population increase and keep numbers lower into autumn.’’
For growers needing to bait, Mr Henry advises:
■Apply bait according to the product 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 mice 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.
‘‘I would also encourage growers and advisers to report and map mouse presence, absence and level of activity using MouseAlert so others can see the scale and extent of localised mouse activity,’’ Mr Henry said.
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.
The GRDC investment into mouse monitoring is a collaboration project between Landcare Research (New Zealand), CSIRO Agriculture and Food and the Invasive Animals Co-operative Research Centre.
■For information about monitoring mouse activity, phone Steve Henry on 0428 633 844 or email firstname.lastname@example.org
Observations can also be sent to Mr Henry via Twitter: @MouseAlert
■Information about mouse control is available via the MouseAlert website at www.mousealert.org.au or the GRDC fact sheet at: https://grdc.com.au/resources-and-publications/all-publications/factsheets/2011/08/grdc-fs-mousecontrol