What does the term "residual toxicity" refer to in fumigation?

Residual toxicity refers to the lingering effects of a fumigant after it has been applied. This concept is crucial in fumigation because it addresses how long the chemical remains effective in controlling pests after the initial application. Understanding residual toxicity helps applicators determine the timing for re-entry into treated areas and when to consider follow-up treatments. By knowing the residual effects, a trained professional can manage risks to human health and the environment. This knowledge also aids in planning effective pest control strategies and compliance with safety regulations. The other options do not capture the long-lasting effectiveness of the fumigant; therefore, they do not accurately define residual toxicity.