Growers on Eyre Peninsula are being urged to remain vigilant for mouse activity ahead of the 2026 seeding program, following the latest seasonal forecast.
Grain Producers SA (GPSA) has released its mice forecast, which shows increasing populations in key cropping regions.
The most recent CSIRO mouse forecast highlights strong evidence of high mouse activity on Lower Eyre Peninsula, as well as other parts of the state such as the Adelaide Plains, Mid North and Lower Yorke Peninsula, reinforcing concerns that growers could face significant pressure at sowing if conditions favour rapid population growth.
The forecast for Upper Eyre Peninsula and the Far West is for low mouse activity.
GPSA chief executive officer Brad Perry said the warning came at a critical time as grain producers prepare to put crops in the ground.
“Mouse activity is already building in parts of South Australia, and with seeding just around the corner, South Australian grain producers need to be alert and prepared to act,” Mr Perry said.
“The CSIRO data is clear; populations are increasing in key grain growing regions, and there is a real risk this could escalate into a broader issue if conditions allow.”
Mr Perry said early monitoring and timely action, such as applying bait, would be critical to minimising damage to emerging crops.
“Grain producers should be out in paddocks now checking for signs of activity, particularly active burrows,” he said.
“Even two or three active burrows per 100 square metres is considered a warning sign before sowing.”
Mr Perry said work was ongoing to improve control options, but current regulatory settings remained unchanged.
“GPSA has established a working group with the Department for Primary Industries and Regions, Grains Research and Development Corporation (GRDC) and CSIRO assessing the current barriers in accessing stronger mouse bait for South Australia grain producers,” he said.
“According to survey data from South Australian grain producers, there is overwhelming feedback that ZP50 is the most effective option to stop the severe impact from mice in our paddocks, however there are currently challenges in gaining access to this tool through the Australian Pesticides and Veterinary Medicines Authority (APVMA).”
The CSIRO report also highlighted the importance of reducing background food sources such as spilt grain, which can significantly reduce the effectiveness of baiting programs.
Mr Perry said the situation reinforced the need for proactive management, particularly given the financial pressures growers are already facing this season.
“Grain producers are already dealing with high input costs and seasonal uncertainty and the last thing they need is avoidable crop damage from mice,” he said.
“This is about being proactive. Monitoring, preparation and early action are important when dealing with increasing mice numbers.”
CSIRO rodent expert Steve Henry, who is one of the lead researchers on GRDC-supported investment into mouse management, said that conditions are ripe for mouse breeding this time of year.
“Mice start breeding at 6 weeks old and have litters of six to 10 pups every 19 to 21 days,” he said.
“Breeding starts in spring and can continue through to late autumn. If conditions are favourable, the rate of increase is dramatic.”
Mr Henry urged growers to monitor their paddocks throughout autumn, taking steps to reduce sources of available food.
“While mouse numbers vary across cropping zones, if present in high numbers they could have devastating impacts on crops being sown in the coming months,” he said.
“It is imperative growers get out of their vehicles, walk into their paddocks and get a good feel for what is going on in respect to current mouse numbers and activity. High stubble loads can hide the signs of mouse activity.”
In South Australia, mouse plagues typically occur every four to six years.
Food left behind from the previous crop provides conditions for mouse numbers to increase rapidly.
GRDC’s key mice management recommendations for growers include:
• Actively gauge mouse numbers by walking through paddocks – use mouse chew cards and active burrow counts to gauge mouse presence and activity. Mouse chew cards can be ordered from GRDC on 1800 11 00 44.
• If mice are present at sowing, bait at or as soon as possible after sowing, to prevent damage to the freshly sown crop.
• Talk to bait suppliers early to ensure timely supply. As with use of any agricultural chemical, use the product in accordance with the label, and report any adverse or off target effects via the
APVMA website. Growers should be aware that only baits containing 25 g/kg zinc phosphide (ZnP) are currently registered for use by the APVMA.
Grain Producers SA encourages growers to report mouse activity and remain engaged with updates as conditions evolve throughout the season.
Mouse activity can be reported using CSIROs tracker MouseAlert at feralscan.org.au/mousealert
