Which of the following methods is commonly used to treat termite infestations?

Soil fumigation is a method commonly used to treat termite infestations as it involves applying fumigants to the soil to eliminate termite colonies. This technique is particularly effective for creating a barrier against subterranean termites, which live in the soil. The gases are able to penetrate the soil and reach the termites where they reside.

Soil fumigation is especially beneficial for treating extensive infestations because it addresses the problem at its source and ensures that the termites cannot return. It is often used when there is heavy infestation and when other methods may not effectively eliminate all the termites present.

The other methods are not as widely utilized for this purpose. Electrocution may be used in some localized instances but is not a standard method for treating termite infestations overall. Heat treatment can be effective for drywood termites but is less common for subterranean types which are typically treated through soil fumigation. Chemical injection focuses more on localized infestations and is effective for spot treatments, but it may not address larger issues as comprehensively as soil fumigation.