Barrier against storage pests
Growers planning to store grain in unsealed storages after this year’s harvest are being encouraged to consider using grain protectants to reduce the risk of insect pest infestations.
The use of protectants combined with meticulous hygiene and aeration cooling are especially useful in storages which are not gas-tight and therefore cannot be fumigated effectively.
Southern cropping region grainstorage specialist Peter Botta said grain protectants were designed to prevent pest infestations – not to control existing infestations.
“A common misunderstanding is that grain protectants kill insects already infesting the grain, but those types of contact disinfestants are no longer available for on-farm use,” he said.
“Therefore, grain must be clean and free of pests before applying a protectant.”
The Grains Research and Development Corporation supports Mr Botta’s work.
In order to give protectants the best chance to defend stored grain, meticulous storage hygiene practices before and after harvest are required.
Mr Botta said cleaning storage sites and harvesting equipment removed harbours where pests could survive, ready to infest the new season’s grain. The addition of aeration cooling also provides an unattractive environment for pests in stored grain.
He reminded growers to always read the chemical label before choosing a protectant to ensure it was registered for use on the grain they intended to apply the product, and that it would target the main insects commonly found in their storage.
As a general guide, protectants are only registered for use on cereal grains and only some, not all, of those protectant products are registered for use on malting barley, rice and maize. No protectants are registered for use on pulses and oilseeds.
Mr Botta implored growers to fully understand the requirements of the targeted markets for their grain before considering application of a grain protectant.
“Some buyers – domestic and overseas – will not take grain that has had protectants applied, so it is critical growers know in advance what those market specifications are so they aren’t limiting their selling options,” he said.
If targeting markets which accept grain that has been treated with a protectant, knowing the maximum residue limits of those markets is also essential.
“As grain markets have become less tolerant to protectants and maximum residue limits, maximum residue limits are monitored scrupulously – accurate application in terms of the correct rate and spread is vital.”
Commodity vendor declarations are also used in many cases to ensure a parcel of grain is only subjected to one application of the protectant to avoid exceeding the maximum residue limits.
Some protectants start deteriorating 48 hours after being mixed with water so growers should avoid leaving prepared protectants for long periods before applying to grain.
The product label will also indicate the anticipated effective life of the protectant on the grain.
The effective life of protectants is shortened if applied to grain above 12 percent moisture content and at temperatures above 27 degrees, or if treated grain is exposed to direct sunlight, which can occur at the end of a shed or in an open bunker.
Further information on grain protectants is available from the GRDC’s Stored Grain Information Hub at www.storedgrain.com au.
CONSIDER PROTECTANTS: Growers planning to store grain in unsealed storages after this year’s harvest are being encouraged to consider using grain protectants to reduce the risk of insect pest infestations.