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Correct Use of Fumigant in Stored Grain Urged

17 January 2011

AUSTRALIA - Australian growers in the fortunate position of having grain to store this year are being provided with timely support to ensure they protect their yields and safeguard their enterprises through the correct use of phosphine for controlling pests in stored grain, says the GRDC.

A Grains Research and Development Corporation (GRDC) survey carried out during 2010 revealed only 36 per cent of growers using phosphine applied it correctly â€" in a gas-tight, sealed silo.

GRDC Manager of Extension and Grower Programs, Tom McCue, says phosphine remains the single-most relied upon fumigant to control stored grain pests in Australian grain production systems, but continued incorrect use is resulting in poor insect control and developing resistance in key pest species.


GRDC Manager of Extension and Grower Programs, Tom McCue, says the best way to prevent resistance is to use phosphine correctly: "That means using it in a gas-tight, sealed silo."
Mr McCue said the best way to prevent resistance was to use phosphine correctly: "That means using it in a gas-tight, sealed silo."

To support growers in the effective application of phosphine, the GRDC has produced a valuable booklet, Fumigating with Phosphine, Other Fumigants and Controlled Atmospheres.

This booklet explains how using phosphine incorrectly contributes to resistance problems and clarifies how to use it most effectively to achieve reliable results. The booklet details the best practice for application, exposure, ventilation and withholding periods.

The publication emphasises the fact that in a silo with minor leaks (not gas-tight) phosphine gas concentrations do not reach the required concentration level, for the necessary period, to kill pests at all life stages.

"The only way to determine if a sealable silo is in fact gas tight is by simply performing a pressure test, which is explained in the booklet," Mr McCue said.

"It's not difficult or complicated and will ensure the phosphine application is effective against all life stages of problem pests, resulting in the best possible control and without increasing resistance."

Mr McCue said glyphosate-resistant ryegrass was an example of the consequences of continuous use of a single mode of action chemical, which has led to resistance, with industry-wide ramifications.

"Unlike herbicides, where resistance can be avoided by rotating chemical group from year to year, there are few alternative stored grain fumigation options other than phosphine."

Mr McCue reminds growers and advisers that last year standards body SAI Global published an Australian Standard (AS2628) for gas-tight sealed silos in response to industry concerns that phosphine fumigation in improperly sealed storages was not killing insects at all life stages.

The standard is based on a new silo meeting a five-minute half-life pressure test and allows growers to refer to an industry benchmark when buying a gas-tight, sealable silo.

The Fumigating with Phosphine, Other Fumigants and Controlled Atmospheres booklet is available for viewing and download via www.grdc.com.au/GRDC-Fumigating-with-phosphinewww.grdc.com.au/GRDC-Fumigating-with-phosphine.

TheCropSite News Desk



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