Question

Which of the following is a pre-emergence herbicide?

• A. Diuron
• B. Butachlor
• C. Proclaim
• D. Ambien

Hint:

Pre-emergence herbicides:
- Applied before weed emergence.
- Examples: Butachlor, Pendimethalin, Atrazine.
- Post-emergence herbicides: Applied after weed emergence.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pre-emergence herbicides are applied after sowing but before the emergence of weeds.
They prevent weed seed germination and early seedling growth, thereby reducing weed competition during the initial crop growth stage.

Step 2: Detailed Explanation:
Butachlor is a selective pre-emergence herbicide widely used in transplanted and direct-seeded rice.
It effectively controls annual grasses and certain broadleaf weeds by inhibiting the growth of germinating weed seedlings.
The other options are not appropriate because:
- Diuron is primarily used in non-crop areas and specific plantation crops.
- Proclaim is an insecticide used for controlling lepidopteran pests.
- Ambien is not a recognized agricultural pre-emergence herbicide.
Hence, Butachlor is the correct choice.

Step 3: Final Answer:
Therefore, the correct answer is (B) Butachlor.