Prevent moisture and pests in stored grain

Prevent moisture and pests in stored grain

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GRDC grain storage extension project manager, Chris Warrick, busy outlining details of grain storage during one of many field days he has facilitated. Hygiene of silos is high on pre-harvest agendas. Photo. Primary Business.

GRDC grain storage extension project manager, Chris Warrick, busy outlining details of grain storage during one of many field days he has facilitated. Hygiene of silos is high on pre-harvest agendas. Photo. Primary Business.

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Grain growers need to make sure their on-farm storage facilities are clean and ready for the expected big yields.

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GOOD hygiene, aeration cooling and regular inspections to monitor for insects are key tools for protecting grain during on-farm storage.

As the harvest is in full swing in the state's North West and machines are moving into crops in the Central West, Grains Research and Development Corporation (GRDC) grain storage extension project manager, Chris Warrick, says there are two challenges for growers this year.

"They will be dealing with high moisture grain during a wet harvest and managing a high volume of grain requiring temporary on-farm storage," Mr Warrick said.

"Rain during harvest has its perils, and higher moisture content is just one.

"Cereal grain harvested over 12.5 per cent moisture content can be held with aeration cooling until it can be dried or blended.

"Small, aeration cooling fans won't dry grain but enable safe storage for a few months."

However, insects are usually the biggest risks to quality grain storage, so growers looking at managing insects must do everything they can to prevent infestations.

"It starts with good hygiene and structural treatments to make sure your facilities are clean of leftover grain and insects that may live in that grain," he said.

"Aeration cooling is also a preventative, while protectants also fall into the prevention category. The spray-on protectant products that deter insects from breeding in grain can be a good option in temporary storages and non-gas-tight storages where fumigation is not a reliable option."

Not just a problem with weevils

HIGH volumes of grain with significant value will possibly be stored on-farm this season.

So, it's no longer a case of putting up a big steel tank (silo), fill it with grain and forget about it, says Grains Research and Development Corporation (GRDC) grain storage extension project manager, Chris Warrick.

"We monitor and manage the crop for the whole growing season, so we need to continue that monitoring and management while grain is in storage," Mr Warrick said.

"But when it comes to insect threats, most farmers think damage is done by weevils."

Most infections will come from a combination of five main pests, - the rust-red flour beetle, rice weevil, saw-toothed grain beetle, flat grain beetle, and lesser grain borer.

Cereal grain can be protected against four of these five pests with the choice of two protectants - spinosad and s-methoprene or deltamethrin and piperonyl butoxide.

"Both protectants are recommended to be rotated each year or two to reduce the chance of insect resistance," Mr Warrick said.

"The remaining pest not deterred by these two protectants is the rice weevil, and unlike the name suggests, it's commonly found in all cereal grains not just rice."

Mr Warrick said grain can be protected from this insect by adding either fenitrothion or chlorpyrifos-methyl to the protectant mix.

Grain buyers should be consulted prior to application to ensure the intended market accepts protectants on the grain. Users of chemical products are urged to read and follow label directions very carefully and ensure they are clear on the withholding period which can be up to 90 days with one product..

When it comes to grain drying, Mr Warrick said one of the misunderstandings was the difference between aeration cooling and aeration drying.

"Aeration cooling prevents mould and insect development with low flow rates of two to four litres of air per second per tonne. Aeration drying requires upwards of 15l of air per second per tonne to remove grain moisture. " he said.

Mr Warrick said storedgrain.com.au was devoted to all aspects of stored grain including a recently updated GRDC GrowNote on Grain Storage, an all-encompassing manual.

There is also a direct assistance phone line - 1800WEEVIL, that will put callers in contact with their nearest grain storage specialist who will answer all questions.

Southern NSW calls will be answered by Chris Warrick and calls from northern NSW and Queensland will be answered by the highly experienced grain storage specialist Philip Burrill.

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