Residual

In pest control, "residual" refers to the long-lasting effect or presence of a pesticide, insecticide, or other pest-control substance after it's initial application. This means, after a pest control application, the substance doesn't just disappear but instead continues to work over a period of time. The residual effect can be a significant factor in the effectiveness of certain types of pest control, like termiticides or rodenticides, as it allows the substance to affect multiple generations of pests. In some cases, depending on the type of pest and the specific pest-control product, this residual effect can last for several weeks or even months. This persistent action ensures a comprehensive pest extermination, and adequate control over potential future infestations.