Phosphine, the one fumigant widely available for on-farm use throughout Australia, is normally supplied as a solid preparation under a number of trade names and in a variety of forms such as tablets, pellets, sachets and blankets. These react with moisture in grain and surrounding air, gradually releasing phosphine gas. Under Australian conditions, the process of release typically takes up to five days.
Grain delivered or transported which has been recently fumigated or is still under fumigation could contain gas and still-active preparations releasing gas.
These could poison or even kill unsuspecting people handling, transporting and using such grain or animals being fed on it.
Don't be tempted to go 'off label' — quite apart from being illegal, think of the consequences.
Phosphine fumigations take time. The label on the can will tell you how long. Typically seven days under fumigation, followed by two to five days ventilation, followed by a further two days withholding period for a total of 11-14 days. This ensures the preparation has finished releasing gas and any gas present has been allowed to escape.
Withholding period mandatory
The fumigated material can only be legally transported once it has been vented for the required time. It can be legally used for human consumption or animal feed only when the withholding period has passed.
Be careful with carbon disulphide,too
Similar problems could occur with carbon disulphide, a fumigant currently registered only in NSW. The grain takes up the fumigant quickly, but only releases it gradually during airing. If the airing period is too short, then dangerous amounts of fumigant may still be present.
With either fumigant there is a perception that increasing the dose will lead to a faster fumigation. Don't forget, application of any pesticide above the label rate is an unacceptable practice in the grain trade and is illegal. It increases the risk of unacceptable chemical residues getting into our food.
Be safe,plan ahead.Remember,fumigation is not a 'quick fix' - take the time to do it safely. Follow the label on the can - it is the law.
North, South, West