Match The Grain Protectant

“Understanding the condition of the silo and hence the options for protecting grain from insect pests is an important decision for farmers who store their own grain”, says Rod McLean of Bayer.

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“Farmers spend about $120/tonne to grow their grain and get it into the bin,” says McLean. “The cost of protecting the grain in the bin will be $0.50 to $3.50/tonne depending on the method used. It seems a pity to risk all that cost by not choosing the correct method of protecting the grain and risking loss of value or even a sale. ”

Market research conducted by Bayer earlier this year shows almost 90% of cereal growers have on-farm storage. Many had a combination of different types of storage but the most common was unsealed. “Of those called “sealed”, 60% were over 10 years old and it is doubtful if they are gas tight,” McLean said. “Many silos are sold as “sealed” but after a few years of use may not pass the Australian Standard as gas tight.”

The market research also showed fumigation using phosphine is the most common method used for grain protection. Research by several State governments shows Australia has insect resistance to phosphine. This is due to it being in use for many years and under-dosing due to failure to achieve sufficient gas concentration for the required period due to poorly sealed silos.

“For successful fumigation you need to maintain the level of fumigant above a minimum for a week or longer depending on the temperature. If the silo is not gas tight this is not possible”, McLean says. 

If a silo is not gas tight the only option is to use a grain protectant like K-Obiol. This is a liquid and so can be used in unsealed silos as well as sheds. (More information is available on K-Obiol at

Some grain protectants have been in use for over 30 years and insect resistance to them has developed. There are several types of insect pests which infest stored grain and they are found throughout the grain growing areas of Australia.

“When we have examined infested grains we often find two or more insect types,” according to McLean. “As different insects have developed resistance to the various grain protectants to get good protection you need to use a combination of grain protectants with different modes of action. K-Obiol in combination with either fenitrothion or chlorpyrifos-methyl gives coverage to all types of insects.”



About Bayer in Australia

Bayer is a world class innovation company with more than 150 years’ history and core competencies in the Life Science fields of healthcare and agriculture. Its products and services are designed to benefit humans, animals and plants.  It has operated in Australia since 1925 and has a long term commitment to the health of Australians, the agricultural industry and the welfare of animals, large and small.  In Australia, Bayer currently employs almost 900 people across the country and is dedicated to servicing the needs of rural Australia and the local community. Bayer is deeply committed to research and development and has a strong tradition of innovation with the development and commercialisation of over 5,000 products and services. The company’s focus on people, partnerships and innovation underpins all aspects of its operations, consistent with its mission, “Bayer: Science For A Better Life.”



Rod McLean, Product Manager, Environmental Science, Crop Science Division, Bayer

T 03 9248 6834 (Tues&Thurs)

M 0413 820 426



Martin Ball, General Manager, Environmental Science, Crop Science Division, Bayer

03 9248 6830




Forward-Looking Statements

This release may contain forward-looking statements based on current assumptions and forecasts made by Bayer Group or subgroup management. Various known and unknown risks, uncertainties and other factors could lead to material differences between the actual future results, financial situation, development or performance of the company and the estimates given here. These factors include those discussed in Bayer’s public reports which are available on the Bayer website at The company assumes no liability whatsoever to update these forward-looking statements or to conform them to future events or developments.