Written by: Peta Florus
What is fumigation?
According to Wikipedia, â€œfumigation is a method of pest control that completely fills an area with gaseous pesticidesâ€”or fumigants â€”to suffocate or poison the pests within. It is used to control pests in buildings (structural fumigation), soil, grain, and produce, and is also used during processing of goods to be imported or exported to prevent transfer of exotic organisms. This method also affects the structure itself, affecting pests that inhabit the physical structure, such as wood borers and drywood termites.â€
According to the NCPC (National Certificate in Pest Control) handbook which is used by our technicians to acquire their certification, â€œfumigation is defined as the act of introducing a toxic chemical into an enclosed space in such a manner that it disperses quickly and acts on the target pest in the gaseous or vapour state. Fumigation is one of the methods for controlling pests in stored products. The goal of fumigation is to confine enough gas for sufficient time to eradicate the target pest, which in normal conditions is achieved in a static chamber under control of one qualified fumigator.â€
Weâ€™d like to unpack this definition so that our readers understand exactly what fumigation is (and isnâ€™t) and where it is meant to be used.
Letâ€™s start off by discussing the â€˜fumigantâ€™
According to the NCPC handbook: â€œFumigants are a group of pesticides that can kill insects where no other form of control is feasible. Unlike aerosols and other contact insecticides, fumigants can exist in a gaseous state. The unique property of fumigants is that as gases they diffuse as separate molecules, which enables them to penetrate into the material being fumigated and to diffuse away afterwards.â€
Basically, a fumigant is a poisonous substance used in the extermination of insects or unwanted pests that could cause harm, contamination or damage to property, grain, soil, produce, etc. These fumigants come in various forms (liquids and solids) but they are converted to a gas during application or when they come into contact with the atmosphere.
Rentokil has a strict protocol around the fumigants we use, and will only add them to our Approved Product List if they have the approval of and are registered with the Department of Agriculture, Fisheries and Forestries (DAFF) and have been rigorously tested by us for efficacy. Our technicians, who are all fully qualified pest control operators, undergo additional, specific fumigation training before any new fumigants are introduced into our business and onto your premises. Part of the training is to only use these products in the manner prescribed by the manufacturer for its intended purpose. The deployment of each fumigant is site specific due to the different properties and behaviour of each gas.
There are 2 registered fumigants which are commonly used globally: Phosphine and Methyl Bromide.
Phosphine (Magnesium Phosphide and Aluminium Phosphide) comes in the form of pellets, tablets or plates, and these react with the moisture in the air to produce a gas. Phosphine is authorised for the fumigation of food products and can be used to control stored product insects (SPIâ€™s) and pests in other commodities. With the correct aeration processes, it will not leave a residue or taint the product in any way.
Methyl bromide comes in a liquid form, presented in a gas cylinder. It is dispensed via shooting lines into the commodity and it converts to a gas when it reacts with the moisture in the air.
Methyl Bromide has been in use for many years, but due to the damage it causes to the stratospheric ozone layer, this product is being phased out globally as finalised in the Montreal Protocol in 1987.
The use of Sulfuryl Fluoride (or Profume) has been approved and registered by the Department of Agriculture and Profume will be phased into the industry as an alternative to methyl bromide. Rentokilâ€™s technical team have already enrolled in various training programmes and are working on a swift implementation of this alternative product.
In order to effectively control pests using fumigation, one needs to take into consideration a number of variables that have an impact on the success of the fumigation treatment:
- The type of pest being treated – is fumigation the most suitable method of resolving the issue, and has there been pest resistance to the fumigant previously?
- The commodity or product being treated – what type of product and severity of the infestation, is it precautionary, or an export requirement?
- The density of the commodity could have an impact on the duration of the fumigation;
- Time frames required – how urgent is it? Phosphine and methyl bromide have different treatment periods;
- Temperature and humidity (or season) play an important role in determining the duration and efficacy of the fumigation process
- The dosage of the various fumigants is dependent on a number of things such as
- Commodity to be treated
- Pest to eradicated
- Time available
- Country or customer specifications
- Health and safety – fumigation is a high risk treatment and ensuring the safety of our customers and staff is of utmost importance. We therefore follow strict safety protocols, starting with a full survey of the task required and a detailed Risk Assessment of our customers’ site.
Our technical team of experts undergo rigorous training to keep our customers and their staff safe at all times during fumigation. As well as ensuring the space is cordoned off before fumigation proceeds, additional gas leakage detection and monitoring apparatus are positioned in the area being treated.
During the fumigation treatment, our technicians wear a full safety kit which includes personal gas leakage detection and monitoring apparatus, as well as specialised breathing apparatus.
All our fumigation treatments comply with relevant legislation which include the manufacturersâ€™ MSDS, government regulations, our own Global rules and regulations, as well as our standard operating procedures which are specific to each task.
With over 45 years of experience in South Africa and 85 years of global experience in fumigation, we are confident in our ability to offer expert advice on any fumigation enquiry you may have. Our services are supported by our local fumigation teams and managers to ensure that any treatment you receive from us meets and exceeds your expectation.