- What is a fumigant?
- Fumigation is a method of pest control that completely fills an area with gaseous pesticides (the fumigant) to control the pests within. It is utilised for pest control in buildings (structural fumigation), soil, grain and produce. It can also be applied when processing goods intended for import or export to prevent the transfer of exotic organisms, including insects, pathogens and nematodes, from one country to another.
- What are the attributes of an effective fumigant?
- An effective fumigant must satisfy several criteria. It should:
1. Target a broad spectrum of pests
2. Be fast acting
3. Be easy to dose and apply
4. Be environmentally friendly (non-ozone-depleting with a low global warming potential)
5. Offer a short holding period
6. Have a low phytotoxicity rating for fresh commodities.
- What types of fumigants are used on grain and why does the market need alternatives?
Traditionally, methyl bromide was used on grain. Due to its high ozone-depletion potential, methyl bromide is being phased out globally under the Montreal Protocol. It is now only permitted on grains intended for export or import. In other words, it cannot be used for domestic storage.
Phosphine (tablets and gas) are used for stored grain although insect resistance in many regions has created the need for new fumigants.
VAPORMATE® is a more recent alternative. It is an environmentally friendly, low-toxicity option that may be used safely and effectively on grains.
- What types of fumigants are available for use on wood and why does the market need alternatives?
Methyl bromide is the most popular fumigant for wood. Due to its high ozone-depletion potential, however, methyl bromide is being phased out globally under the Montreal Protocol.
Phosphine is also used on wood, although the fumigation period (10 days) can make this product problematic.
Alternatives such as heat and cold treatment are not yet commercially viable in most countries.
Hydrogen cyanide is used in a small number of countries and has just been re-introduced into Europe.
EDN® is a more recent alternative. It is an ozone-friendly alternative to methyl bromide, limiting the impact of pests and disease on timber and in agriculture.
- In what scenarios is fumigation required or mandatory?
Fumigation is mandatory for imports and exports. The importing country dictates the fumigant that needs to be used in many cases and this renders a specific type of treatment mandatory (e.g. with methyl bromide).
In some cases a product may be imported as “pest-free”. In this case, the exporter can use the treatment of their choice as long as it does not exceed the Maximum Residue Levels for commodities intended for human consumption.
If a product is exported as “pest-free” and stopped at a port because it contains insects, it will generally receive a dose of methyl bromide despite the phytotoxic results.
- What conditions affect fumigation effectiveness?
Effectiveness is largely determined by:
• the dosage of the fumigant
• the duration of exposure
• the temperature and
• the moisture content of the commodity.
In addition, for optimum results the fumigation chamber must be effectively sealed during the fumigation process and the levels of fumigant should be monitored to ensure they remain above the dose required to manage the pests in question.
- Can insects show resistance to fumigants? Does this change over time? What factors influence this?
Insects may develop resistance to any chemical. This happens when insect populations are frequently exposed to sub-lethal doses. This allows the rare individual insects with new resistance gene to survive treatment and continue breeding, passing on their resistance. Repeat fumigations favour the insects that carry the resistance gene by allowing them to survive, but killing normal, susceptible insects.
Insect resistance is reported internationally with phosphine and is generally a result of fumigations in unsealed silos and bunkers or where fumigations are not conducted in accordance with best practice.
More information is available here:
- What trends are currently defining the fumigation market?
Food safety is a megatrend the world over as consumers are demanding greater control over residues in the foods they consume. This is prompting many countries to switch to safer fumigants.
In addition, the international food trade continues to grow, flanked by stricter, safety-driven fumigation rules.
- What is a pest?
- A destructive insect or other animal that attacks crops, food, livestock, etc.
- What is the difference between pest control and management?
- Control is part of a pest management plan. In other words, you fumigate in some cases if you find pests. As part of a wider pest management plan, many farmers try to avoid/mitigate and control pests throughout the product lifecycle.
- How are pests currently controlled?
- Fumigation is compulsory to control the risk of pests (including damage in transit) and to deal with identified cases of pest incursion.
- What practical pest management methods/practices are used for stored-grain insects?
- The following measures can help control pests:
• The use of sealed silo structures
• Management of moisture levels
• Rotation of chemicals
• Responsiveness to incursion
• Supply chain management.
- What trends are currently defining the pest control industry?
- Insect resistance is a main driver for more effective pest control solutions.
The market is also under pressure to resolve issues with global Maximum Residue Levels of some chemicals.