Which term describes a herbicide that remains on the plant surface and does not move inside?

• A. Postemergent
• B. Systemic
• C. Translocated
• D. Contact

Answer: (D)

Herbicides can act by either staying on the plant surface or moving inside the plant. A contact herbicide stays on the surface it’s applied to and does not move through the plant’s vascular system, so it only damages the tissues it actually touches. This is why coverage matters a lot with contact products—they rely on contact with green tissue to work. In contrast, systemic or translocated herbicides are absorbed and moved through the plant (via xylem/phloem) to affect other parts that weren’t directly treated. The timing term postemergent refers to when the herbicide is applied (after weeds have emerged) and does not describe movement within the plant. Therefore, the term that best describes a herbicide that remains on the plant surface and does not move inside is contact.