What is a selective herbicide?

What is a selective herbicide?

• A. A herbicide that kills all plants it contacts
• B. A herbicide that kills one type of plant but does not seriously affect other types
• C. A chemical that increases plant growth
• D. A pesticide with no selectivity

Answer: (B)

Selective herbicides are designed to control specific weed species while allowing the crop to survive. They work by taking advantage of differences between the weed and the crop—such as how the plant absorbs the chemical, how it moves within the plant, or how its physiological targets differ—so the weed is killed or inhibited while the crop remains relatively unharmed at the labeled rate. This is why the described option fits best: it kills one type of plant but does not seriously affect other types. In contrast, a non-selective herbicide would kill all plants it contacts, and a chemical that increases growth isn’t a herbicide at all, while a pesticide with no selectivity is just another way of saying it would damage the crop too.

Selective herbicides are designed to control specific weed species while allowing the crop to survive. They work by taking advantage of differences between the weed and the crop—such as how the plant absorbs the chemical, how it moves within the plant, or how its physiological targets differ—so the weed is killed or inhibited while the crop remains relatively unharmed at the labeled rate. This is why the described option fits best: it kills one type of plant but does not seriously affect other types. In contrast, a non-selective herbicide would kill all plants it contacts, and a chemical that increases growth isn’t a herbicide at all, while a pesticide with no selectivity is just another way of saying it would damage the crop too.