IF THE loss of up to 2.5 tonnes a hectare of feed barley due to fierce winds was not enough farmers through parts of Victoria and South Australia are being warned they will now actively need to monitor for an increase in mice numbers.
Mice numbers were low last year, well below economically damaging levels in virtually all cropping zones however experts have warned they could quickly breed up due to the abundance of food.
Wind damage in November and December last year was particularly damaging on barley crops and now with all the grain on the ground it provides an easy feed source for mice.
A solid grazing is recommended to lower the food source, while for those without livestock cultivation may be required.
In particular, the Grains Research and Development Corporation (GRDC) is warning farmers in the northern Wimmera and southern Mallee in Victoria and South Australia's Lower Eyre and Yorke Peninsulas to be vigilant following the heavy head loss at harvest.
Barley is the major food source but there were also reports of significant numbers of lentil and canola seed on the ground.
With such a large amount of grain on the ground, rodent experts are warning of the risk of a rapid increase in mouse populations ahead of sowing of this year's winter crops.
Lead researcher Steve Henry from CSIRO, Australia's national science agency, says grain left in paddocks could sustain mouse breeding and trigger higher mouse numbers which had been at relatively low levels throughout 2019.
"Not only will a large amount of grain on the ground provide mice with a ready food source, it also means there is a reduced likelihood of mice discovering bait," says Mr Henry, whose mouse-related research is through a GRDC investment.
"If strong winds have resulted in two tonnes/hectare of grain on the ground in some areas, that equates to up around 4000 grains per square metre.
"The challenge for growers is to reduce the food load for mice."
Mr Henry says putting sheep on stubbles and strategic cultivation to bury grain will assist with food reduction, and he encourages growers to spray out any summer germinations.
Mr Henry said it was critical for growers to get out of their utes and walk into paddocks to obtain an accurate understanding of current conditions in terms of the amount of grain on the ground and signs of mouse activity.