What is Fumigation ?
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 implied that a fumigant act as gas in the strictest scenes of the word.
Why Fumigation is Necessary ?
Commodities such as food-grains, oilseeds, pulses, spices, tobacco, textile, timber etc., which are major items in today’s export market, are highly susceptible to infestation from stored grain pests during storage are transit. This infestation can cause extensive damage. Also, the strict quarantine and regulatory requirements of various nations mandate a pest-free shipment. Fumigation (or the use of a gas in an enclosed space to kill pests) as a curative control technique is an indispensable requirement; lethal to all stages of insect development- eggs, larvae, pupa and adult, it not only kills live infestation, but also helps to check the spread of unwanted pests from one country to another.
How Infestation Happens In The Cargo ?
Fumigation of export 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 hold 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 better option that 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 packaging materials since untreated packaging materials are prone to infestation and become carriers for introducing new pests to other countries. Therefore wooden packaging materials should be treated prior to export. Fumigation is carried out mainly with two types of fumigants, Methyl Bromide & Phosphine.