Trials hosted by the Mingenew Irwin Group (MIG) have demonstrated that aeration can reduce insect burdens by an average of 60 per cent in stored seed grain, and deliver cost savings of about $2 per tonne.
Grains Research and Development Corporation (GRDC) Western Regional Panel member and Mingenew grower Darrin Lee was one of four growers to host the trials, and said he was astounded by the visual difference between the contents of insect traps set at the aerated and non-aerated silos.
“When I checked the insect traps I was staggered by the difference – I didn’t realise there would be so many insects and pests in the non-aerated silos,” he said.
Under the three-year project, MIG partnered with The University of Western Australia and the Kondinin Group, with support from the GRDC and the Plant Biosecurity Cooperative Research Centre, to assess the effectiveness of aeration in improving stored grain quality.
While aeration will not kill insects, the MIG trials demonstrated that it can considerably slow insect life cycles and reduce insect densities by an average of 60 per cent compared with the non-aerated silos, and in one case by 72 per cent.
Reducing insect burdens in stored grain is part of the GRDC ‘National Grain Storage Extension Project’ strategy to prevent the spread of insect resistance to phosphine - the only effective fumigant available to growers for controlling grain storage insects.
The aeration system in the Mingenew trials reduced temperatures in the grain to an average of 19°C, with the temperature in aerated silos being as much as 12°C lower than in the non-aerated silos, which helped to reduce the rate of insect reproduction and growth.
There was also an improvement in seed viability, with only 2.3 per cent of unviable seed in the aerated silos, compared with 4.6 per cent in non-aerated silos.
A cost-benefit analysis, conducted by GRDC grain storage extension officer Ben White, demonstrated that growers were $2/t better off with aerated silos when storing seed wheat at current prices.
The analysis included the cost of aeration equipment and controllers, which depreciated over the three years of the project.
The total calculated cost of storing grain in an aerated silo was $11.56/t, compared with costs estimated at $13.50/t for storing grain in non-aerated silos – including the cost of storage and fumigations to control insects, as well as seed losses, based on a seed cost of $300/t.
Mr Lee said the aeration system used in the trials was simple to use, could be retrofitted, was not overly expensive and could potentially be linked to eight silos.
“There was also no need to use toxic chemicals – how clean and green is that?” he said.
“I have always been diligent when it comes to grain storage practices, including the use of good, sealed silos and hygiene measures.
“But being involved in these trails has reinforced to me the vital importance of farm hygiene and biosecurity measures.”
Mr Lee said he was now using aerated, chemical-free sealed storage silos to store albus lupins intended for the human consumption market.
More information about the trial is available in the GRDC Grain Storage Supplement. It is was included in the November-December 2015 edition of the GRDC magazine Ground Cover.
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Practical information about all aspects of grain storage is available on the GRDC Stored Grain Information Hub storedgrain.com.au.
By investing in grain storage research, the GRDC aims to support growers to introduce and maintain excellent stored grain management for human consumption, stockfeed and seed.
Darrin Lee, GRDC
0427 281 021
0407 941 923
Natalie Lee, Cox Inall Communications
08 9864 2034, 0427 189 827
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