WITH more growers opting to store grain for extended periods, growers are reminded of the benefits of gas-tight sealable storage in controlling and preventing insect pest infestations in stored grain.
Growers also have access to the Grains Research and Development Corporation 1800 WEEVIL hotline, which provides a national team of specialists to call for information about grain storage management.
Grain storage specialist Chris Warrick said while there was more gas-tight storage on-farm than ever before, he was surprised to be still receiving calls from growers without any way to reliably control a pest infestation.
“There are no effective contact insecticides registered for insect pests, meaning the only reliable way to kill them in stored grain is fumigating in gas-tight, sealable storage,” Mr Warrick said.
“Achieving the necessary concentration over time to effectively control all life stages of insect pests through fumigation or controlled atmosphere is only achievable in gas-tight storage.”
Some growers have attempted retro-sealing older silos to improve the seal, but the process is often expensive and not always reliable in the long term.
“If a silo was built gas-tight sealable from new, resealing is an option I would consider, but a silo that was never designed to hold gas is very difficult to retro-seal and remain sealable for years to follow,” he said.
“Hygiene and structural treatments, aeration cooling, protectants and monitoring are all pest prevention options which can be used to reduce the likelihood of issues in stored grain, and you can retrofit aeration cooling systems.
“But the only way to control an infestation is with fumigation or controlled atmosphere in gas-tight storage.”
Information and messaging about the requirement for gas-tight storage is not new and Mr Warrick said a common question from growers yet to take the advice was “which chemical can I spray on the grain to kill the weevils”?
“The spray-on products available now are protectants, designed to be applied on clean grain to prevent an infestation. The first thing to understand is there is no longer any spray-on product to reliably kill an infestation of insects in grain,” he said.
“Growers without any gas-tight storage should consider investing in some so they have the option to at least batch-fumigate when required.”
Whether retro-sealing or buying new storage, it was advised to insist the silo meets Australian Standard 2628 and ensure the silo is guaranteed to meet a five-minute half-life pressure-test (AS2628).
“If you verify it on completion of installation then pressure testing before each fumigation is a quick and easy way to ensure all hatches are sealing,” he said.
A joint report by the Kondinin Group and GRDC grain storage extension team is available for free to assist growers in selecting silo manufacturers: storedgrain.com.au/kondinin-group-research-report-grain-silos-2022.
