What Is a Fumigant?

Fumigants are the chemicals used in fumigation, a pest control process that involves filling an area with poisonous gas to kill the pests.

Types of Fumigants

Fumigants come in gas, liquid and solid forms. Gases such as hydrogen peroxide remain in gas form when put in a room at normal temperature. Liquids such as carbon disulfide evaporate into gas on contact with the air. Solids such as methyl bromide and phosphorus trihydride are exposed to oxygen for a chemcial reaction that produces hydrogen phosphate gas.

Properties of Fumigants

Most fumigants are lethal to insects and similar creatures. Each fumigant, however, has certain attributes that define its specific usage. For example, a heavier type of fumigant takes a long time to diffuse through an area and needs an outside force such as gravity to diffuse successfully. Examples of heavier fumigants include chloropicrin and sulfuric phosphate. Ideally, heavy fumigants are used when the area is heavily infested with pests.

Lighter fumigants such as hydrogen cyanide and aluminum chloride diffuse at a very fast rate. These type of fumigants often are used to destroy pests that are emerging but have not yet invaded the entire area. Other factors that affect which fumigant to choose include the moisture in the area, the presence of outside materials like dust, and the temperature.

Uses and Process

Fumigants are used in places that range from food warehouses to processing plants to grocery stores to keep food from being infested with pests. Farmers use them to destroy pestilent plants and insects that are harmful to crops. Regardless of the place, the process for applying fumigants is the same. First you seal the area tightly. Then you pour the fumigant into the area and wait until the pests are killed. After that, ventilate the air to clear away the fumigants and make it safe to enter.

Disadvantages

Chemicals used as fumigants can explode or may cause a fire. Often, they leave behind a nasty odor that can be fatal to humans. However, when fumigants are applied by a certified professional with the right equipment, these risks are reduced. For safety reasons, applying fumigants should never be done alone.

Additionally, fumigants can negatively affect the environment. A fumigant known as methyl bromide is known to deplete the ozone layer, and many countries have banned its use.

How Fumigants Kill Pests

Fumigant particles affect an insect's respiratory system, choking and killing it. However, some insects such as the codling moth and the weevil have the ability to close off this area of their anatomy when exposed to the poisonous gas. As a result, it may take longer for them to die.

References

• Methyl bromide