Which option describes a pesticide that does not move within the plant and acts only at the site of application?

• A. Systemic Herbicides
• B. Contact Herbicides
• C. Residual Pesticides
• D. Selective Pesticides

Answer: (B)

A pesticide that doesn’t move within the plant and works only at the site of application is a contact pesticide. The key idea here is translocation: some pesticides are absorbed by the plant and travel through the xylem or phloem to other tissues, providing broad or systemic coverage. In contrast, contact pesticides stay where they are sprayed and affect only the plant tissues they actually touch. Because they don’t move through the plant, they won’t control pests hidden inside leaves or other tissues that weren’t contacted by the spray.

This differs from systemic pesticides, which are taken up and moved around inside the plant; residual pesticides, while they may persist in the environment or on surfaces after application, aren’t described by movement within the plant; selective pesticides are about the spectrum of pests they affect, not their movement.