1. Insects need oxygen for respiration. With carbon dioxide fumigation, much of the oxygen in the storage bin is replaced by carbon dioxide that suffocates, dehydrates and also produces toxic chemicals in the blood of the insects.
2. To be effective, elevated carbon dioxide levels must be maintained until all insects die.
3. The required exposure time depends on the percentage of carbon dioxide and the temperature of the grain. The cost of CO2 fumigation is high.
1. Phosphine fumigation is undertaken by using tablets and pellets.
2. These tablets and pellets release phosphine gas when they come into contact with humid air. Phosphine is toxic to all insects.
3. When insects are exposed to fumigation in a sealed environment all stages of development from the eggs, larvae, pupae to adults are killed.
4. Phosphine does not impair the grain nor leave residues that could be hazardous to the consumer when correctly applied and the grains aerated.
1. The careful planning and management of fumigation may be incorporated into Integrated Pest Management system so that fumigants can be used effectively and safely in combination with other control methods.
2. This will minimise the channels of insect resistance to fumigants, reduce the residue in food material and greater occupational safety and less environmental pollution.
Disadvantages of Zinc Phosphide
1. Necessity of prebaiting,
2. Low killing around 40 – 50 %,
3. Induce bait shyness.
4. Toxic to non target species,
5. Chances of secondary poisoning are more.
1. Quick killing
2. Small quantity of chemical is required
3. Single feeding
4. Population can be brought down immediately.