It is a process where a fumigant which is a chemical at required temperature and pressure can exist in a gaseous state in sufficient concentration which will be lethal to given pest organism. This definition implies that a fumigant act as gas in the strictest sense of the word. (Munro 1961)
Why Fumigation is necessary?
Transporting goods in ships and aircrafts between countries using containers is an economic and well established practice. Fumigation becomes necessary in order to keep away exotic pests and diseases entering into the country while permitting reasonably rapid clearance of containers. Timber insects pose a significant Quarantine risk in all countries and accordingly all wooden packing material used in the export packing should be fumigated. By carrying out fumigation at the port of loading clearance of the container at the discharge port can be done without any infestation problem.
How Infestation happens in Export & Import Cargo?
Fumigation of Export & Import Cargo becomes very essential because there are possibilities of hidden infestation in the cargo. Infestation of cargo can happen due to following factors.
(a) High moisture level in the cargo
(b) The place where cargo has been stored prior to shipment
(c) During the time of transit Infestation may occur due to previous residues that would be present in cargo, container and ship holds that would affect the cargo significantly.
The infestation rapidly develops during the voyage period and when cargo reaches the port of discharge it is re-fumigated again at the cost of exporter or the buyer. It is always good to carry out fumigation prior to export to avoid huge fumigation expenditure and handling cost at the port of discharge.
As it is said “Prevention is better than cure”, it is necessary to follow good sanitation and scientific storage methods for maintaining the cargo in sound condition prior to export.
Fumigation operation is effective and a better option than any other methods of pest control because in fumigation process the fumigant circulates and spreads to all areas of infestation whereas spraying operation or other methods of pest control will be less effective.
Another important thing that needs attention is treatment of packing material since untreated packing materials are prone to infestation and become carriers for introducing new pests to other Countries. Therefore wooden packing material should be treated prior to export.
Fumigation is carried out mainly with two types of fumigants: 1) METHLY BROMIDE GAS 2) PHOSPHINE GAS TABLETS.