What type of pesticide can immediately eliminate pests inside a structure but allows for re-infestation immediately after application?

The correct response is a fumigant. Fumigants are volatile chemicals that are used to eliminate pests within an enclosed space, such as a building or a storage structure. They work by being dispersed as gas, allowing them to penetrate various materials and reach pests that may be hidden in cracks, crevices, or other inaccessible areas. This type of pesticide is particularly effective for comprehensive pest control, as it can kill a wide range of pests, including insects and rodents, and often does so quickly.

However, a significant characteristic of fumigants is that they do not leave a residual effect after the treatment. Because they evaporate and dissipate quickly, once the environment is cleared of pests, it becomes susceptible to re-infestation almost immediately if new pests enter the area. This distinguishes fumigants from other types of pesticides, which may have longer-lasting effects that deter or prevent future infestations.

In contrast, insecticides typically have residual properties that can continue to kill pests over time, while herbicides are designed specifically to target plants rather than pests, and repellents serve to deter pests without necessarily killing them.