Which term best describes a pesticide that is applied and remains where applied without moving within the plant?

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

Answer: (A)

Pesticide movement in plants hinges on whether the compound is translocated. Some products are absorbed and moved through the plant’s vascular system to reach distant tissues—these are systemic. Others stay exactly where they’re applied and don’t move inside the plant, so they only affect plant parts they touch—that’s the hallmark of a contact product. When a herbicide remains on the surface and doesn’t move through the plant, it’s acting by contact rather than by distribution throughout the plant.

So the term that best describes a pesticide that is applied and remains where applied without moving within the plant is contact herbicide. Residual refers to persistence after application, not movement inside the plant, and selective describes the range of pests affected rather than how the chemical moves in the plant. Systemic would be the opposite, since systemic products move within the plant. Paraquat is a common example of a contact herbicide.