What is the best example of a selective type of control?

What is the best example of a selective type of control?

• A. Nonselective herbicide
• B. Preemergent herbicide
• C. Selective postemergent herbicide
• D. Soil-active treatment

Answer: (C)

Selective control means using a treatment that targets specific weeds while sparing the crop. A selective postemergent herbicide fits this best because it is applied after the weeds have emerged, and it is formulated to be toxic to certain weed species while the crop remains tolerant. This timing lets the chemical act on actively growing weeds while the crop survives due to its tolerance or metabolic differences. For example, 2,4-D is a classic selective postemergent herbicide used to control broadleaf weeds in many crops without harming the crop itself. In contrast, a nonselective herbicide would kill both crop and weeds, so it isn’t selective. A preemergent herbicide acts before weeds germinate and can be selective in some cases, but it isn’t about killing established weeds after emergence. A soil-active treatment works in the soil and can affect any plant roots that grow into it, so it isn’t inherently selective toward a specific crop-weed pair.