Thorough fumigation is the only effective way to kill stored grain pests after grain is in the storage bin. Fumigants will kill the insects that are in the bin, but they do not prevent reinfestation. An airtight bin is essential for effective fumigation. There should be at least 1 foot of space between the top of the bin and the surface of the grain. The top surface of the grain should be level.
Fumigants form poisonous gases and they are extremely dangerous.
At least two people should be present when fumigants are applied. Since aluminum phosphide is formulated as tablets and pellets, it is easy to apply. The phosphine gas it generates has exceptional penetrating ability and does not adversely affect seed germination. Even though the gas is highly toxic, this method of fumigation is not considered exceptionally hazardous because the gas is not released for the first 1 to 2 hours after the tablets or pellets are placed in the bin. Be careful to prevent the tablets or pellets from coming into contact with free-standing water, either inside or outside the bin.