Which statement about contact herbicides is true?

Which statement about contact herbicides is true?

• A. Kills plants quickly, within hours of application
• B. Are always selective
• C. Move through the plant to kill the root
• D. Only used on woody plants

Answer: (A)

Contact herbicides injure plant tissues at the point of contact rather than moving through the plant to reach the roots. Because they act directly where they touch, the damage appears quickly and the touched tissue can die within a short time, often within hours after application. This rapid, local action is what makes this statement true. They are not guaranteed to be selective; many are non-selective and will kill any plant tissue they contact. They do not rely on translocation to the root to cause mortality, which is what systemic herbicides do. And they are not limited to woody plants—they’re used on a range of weed types, both herbaceous and woody.

Contact herbicides injure plant tissues at the point of contact rather than moving through the plant to reach the roots. Because they act directly where they touch, the damage appears quickly and the touched tissue can die within a short time, often within hours after application. This rapid, local action is what makes this statement true. They are not guaranteed to be selective; many are non-selective and will kill any plant tissue they contact. They do not rely on translocation to the root to cause mortality, which is what systemic herbicides do. And they are not limited to woody plants—they’re used on a range of weed types, both herbaceous and woody.