Which herbicides do not move within the plant and are effective only where applied?

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

Answer: (C)

Herbicides move inside the plant in two broad ways: some are systemic and travel through the plant’s tissues to kill growth from roots to shoots, while others stay where they are applied and do not translocate. Those that do not move within the plant and are effective only where applied are contact herbicides. They work by damaging the plant tissues they touch, so control is limited to the parts of the plant that come into direct contact with the spray. They don’t travel through the xylem or phloem, which is why their effect is localized to the treated surface.

Systemic herbicides are the opposite behavior—they move within the plant, providing control beyond the point of contact. Residual pesticides describe how long the product remains active in the environment after application, not how it moves inside the plant. Non-selective refers to the range of species affected, not the plant movement; some non-selective products can be either contact or systemic, but the term itself isn’t about whether the herbicide moves within the plant.