Which of the following statements about Fumigants is NOT true?

Fumigants are indeed a unique category of pesticides that function primarily as gases. The correct choice highlights that they do not maintain a long-lasting residual effect, which is a characteristic often associated with solid or liquid pesticides that can leave residues on surfaces.

Fumigants are designed to penetrate materials and spaces, killing pests quickly upon exposure to high concentrations. However, they generally dissipate rapidly once the application is complete, which is why they do not leave a lasting residue like some traditional insecticides. This transient nature allows for effective pest control within enclosed areas but means that fumigants are typically not relied upon for prolonged pest management.

In contrast, the other statements about fumigants are true: they are inhaled by insects through their spiracles, they remain gaseous at room temperature, and they are lethal to a wide range of living organisms when present in high concentrations. Understanding these properties is essential for effective use and safety measures when working with fumigants in pest control practices.