What is the primary characteristic of fumigation?

Fumigation is primarily characterized by the process of sealing a location and filling it with a gas that is toxic to pests. This method is effective for controlling a wide range of pests and is typically used in enclosed spaces where the gas can permeate and penetrate materials to reach pests that might be hidden or difficult to eliminate through other means. The sealing of the area is crucial, as it allows for the concentration of the fumigant to remain high enough to ensure effective pest control. This characteristic differentiates fumigation from other pest control methods that may involve contact insecticides or surface treatments, which do not require encapsulation of the area.