Fumigation, Methyl Bromide and Recent Government Order

Recently, the government has asked foreign exporters to fumigate their wheat cargoes with methyl bromide at the ports of origin only. So far, such fumigation was done at Indian ports. Since the recent government order is to get the cargoes fumigated with Methyl Bromide at port of origin, this decision would lead to halt in imports from Europe and other parts where Methyl Bromide is banned. The government seems to have taken to discourage wheat imports because the country has enough storage of the grain.

Important Facts

Most pest control procedures usually involve the applications of chemicals including fumigants. Aerosols and residual insecticides. Fumigation is considered to be the most effective method for insect control because under controlled temperature, the fumigants can penetrate into the packaging of the grains and kill all stages of insect development including eggs, larvae and adults. However, the fumigant materials are highly toxic and need to be handled with utmost care. It is the toxicity that makes fumigants highly effective.  The widely used fumigants include Methyl Bromide, Phosphine, 1,3-dichloropropene, chloropicrin, formaldehyde, hydrogen cyanide, iodoform, methyl isocyanate etc.

There are several methods to do fumigation, for example, adding the gas into an enclosure called fumigant chamber or silo; or structure such as processing plant; or the gas tight sheets. It is done for a specific time and after that the container or building is ventilated for sufficient time.

Methyl Bromide

Two most common fumigants used for stored grains are methyl bromide (CH3Br) and Phosphine (PH3). However, Methyl bromide has been phased out in most countries under Montreal Protocol because it is classified as a serious ozone-depleting substance.