Bunker down against mouse infestation of stored grain
Southern cropping region grain growers planning to store grain in bunkers are advised to locate bunker storages a considerable distance away from this year’s crops to avoid potential mouse infestation.
A large amount of grain likely to be left on the ground after harvest of this year’s high-yielding crops could promote a surge in mouse numbers and activity, and storage experts warn that grain stored in bunkers established close to harvested crops could be at risk.
Grain storage specialist for the southern cropping region, Peter Botta, says growers need to give serious consideration to where they locate bunkers, how they are set up and their ongoing management.
“With such big crops this year, more grain is likely to be spilt than usual, even if growers are careful,” says Mr Botta, whose work is supported by the Grains Research and Development Corporation (GRDC).
“We can see that there is potential for a problem with mice – so meticulous attention needs to be given to bunker storages.
“I strongly encourage growers to locate their bunkers as far away as possible from any cropping areas so that the likelihood of mice travelling from crop stubbles to bunkers is reduced.
“And when tarping the bunkers, make sure that all folds and creases are eliminated so that entry points for mice are minimised.”
Mr Botta says if baiting of mice is required, avoidance of grain contamination is critical.
Other general requirements for successful bunker storage include a well-prepared and compacted pad that is sloped to drain water away from the site.
Hay bales should not be used in the construction of bunker walls, according to Mr Botta.
“They might be a cheap alternative for creating walls but they lead to serious issues when treating stored grain insect pests,” he says. “During gassing, the bales act as a safe harbour for insects which then move back into the stored grain after treatment.”
Mr Botta says effective fumigation of grain stored in bunkers is difficult to achieve. Because a bunker can’t be pressure tested for gas tightness, monitoring equipment is required to ensure gas concentration remains at a lethal concentration for the required period of time to kill pests at all life stages.
“Poor fumigations in bunkers leads to resistant insects which are already costing growers and the wider industry more money to control.”
Attention to detail and close, ongoing scrutiny and management of bunker storages is critical, according to Mr Botta.
“Overflow storage is not ideal storage. It’s important to remember that bunkers are a form of temporary storage and therefore grain should be moved into permanent storage as soon as the opportunity becomes available.”
Further information on temporary storage best practice is available from the GRDC’s Stored Grain Information Hub at http://www.storedgrain.com.au.
The GRDC’s Stored Grain National Information Hotline is also available to help growers with all their grain storage investments and practices. By phoning 1800 WEEVIL (1800 933 845) growers will be put in contact with their nearest grain storage specialist.
To support growers with their on-farm grain storage preparations, the GRDC has released a Stored Grain app for iPhones and iPads. It can be downloaded for free from the iTunes store, or via the GRDC Apps page.
Peter Botta, PCB Consulting
Sharon Watt, Porter Novelli