What do contact herbicides primarily do?

What do contact herbicides primarily do?

• A. Kill underground roots
• B. Kill top growth but do not prevent resprouting
• C. Move throughout the plant to kill roots
• D. Only kill mature plants

Answer: (B)

Contact herbicides act only on the plant tissue they touch and do not move through the plant. Because they don’t translocate to the roots or other underground parts, they quickly kill the foliage that contact herbicide contacts, but the roots and underground structures often survive. That’s why they’re best described as killing top growth while not preventing regrowth from the root system, making resprouting possible after treatment. If the goal is to kill the entire plant including roots, a systemic herbicide that moves within the plant would be required.

Contact herbicides act only on the plant tissue they touch and do not move through the plant. Because they don’t translocate to the roots or other underground parts, they quickly kill the foliage that contact herbicide contacts, but the roots and underground structures often survive. That’s why they’re best described as killing top growth while not preventing regrowth from the root system, making resprouting possible after treatment. If the goal is to kill the entire plant including roots, a systemic herbicide that moves within the plant would be required.