Herbicide selectivity is defined as the ability of a herbicide to kill certain weed species without significant injury to crops.

• A. True
• B. False
• C. Sometimes
• D. Not defined

Answer: (A)

Herbicide selectivity means the chemical can control certain weeds while leaving the crop unharmed when used as directed. This relies on a differential response between crop and weed—the herbicide disrupts or kills the weeds, but the crop tolerates the treatment due to factors like how the plant absorbs, moves, or detoxifies the chemical, or where the herbicide acts in each plant. In practice, selectivity is what makes a product useful in a specific crop: you get weed control without crop injury, whereas non-selective products would injure or kill the crop as well. Keep in mind that field results can vary with rate, timing, and environmental conditions, but the core idea is this built‑in differential tolerance that allows selective weed control.