What is a primary benefit of using residual pesticides?

• A. They require more applications over time.
• B. They help reduce the number of applications needed to control persistent pests.
• C. They are ineffective against deep-rooted weeds.
• D. They always kill only surface pests.

Answer: (B)

Residual pesticides stay active in the environment after application, giving continued pest suppression well beyond the initial spray. The big benefit is extended protection, so you don’t have to reapply as often. This is especially helpful for pests that persist or re-infest a turf area, because one application can cover multiple coming events over a period of time.

In practice, this means fewer applications and less labor, while still keeping pests under control during the active period of the product. Of course, how long the residual lasts depends on the chemical, the rate used, weather, and the target pest, so you plan applications around the expected duration of control and resistance management.

The other statements don’t fit because residuals are defined by their lasting activity, not requiring more applications; their effectiveness isn’t limited to surface pests only, and their activity isn’t universally ineffective against all deep-rooted weeds.