What is a defining characteristic of non-residual pesticides?

Non-residual pesticides are characterized by their effectiveness only during the application time. This means that they do not persist in the environment after being applied, which is a key trait distinguishing them from residual pesticides that remain active for longer periods. The primary function of non-residual pesticides is to act on target pests at the moment they are applied, rather than providing ongoing control once the application has ceased.

This temporary efficacy is useful in situations where short-term pest control is desired, or where there is sensitivity to the chemical remaining in the environment due to safety or regulatory concerns. Non-residual pesticides are designed to break down quickly, mitigating risks to non-target organisms and reducing environmental impact.

The other options convey characteristics that do not align with the nature of non-residual pesticides. For instance, they do not remain active for extended periods or have no effects after application. Additionally, while some non-residual pesticides may be safer for non-target organisms, this does not categorize them as safe for all organisms, as safety can depend on various factors including the specific chemical, concentration, and the organisms involved.