Which term describes herbicides that move within a plant?

Which term describes herbicides that move within a plant?

• A. Translocated (Systemic)
• B. Contact
• C. Preemergent
• D. Nonpersistent

Answer: (A)

The key idea is that some herbicides move inside the plant after absorption, reaching other tissues and growth points rather than killing only the sprayed surface. These are translocated or systemic herbicides. They travel through the plant’s vascular system (xylem or phloem) to new growth and roots, so the entire plant can be affected even if only part was sprayed. Glyphosate and 2,4-D are common examples of this type. In contrast, a contact herbicide kills only the tissue it directly touches and does not move within the plant. A preemergent herbicide is applied to the soil to prevent germination, not to move inside established plants. Nonpersistent refers to how long the chemical remains active in the environment, not its movement inside the plant.

The key idea is that some herbicides move inside the plant after absorption, reaching other tissues and growth points rather than killing only the sprayed surface. These are translocated or systemic herbicides. They travel through the plant’s vascular system (xylem or phloem) to new growth and roots, so the entire plant can be affected even if only part was sprayed. Glyphosate and 2,4-D are common examples of this type.

In contrast, a contact herbicide kills only the tissue it directly touches and does not move within the plant. A preemergent herbicide is applied to the soil to prevent germination, not to move inside established plants. Nonpersistent refers to how long the chemical remains active in the environment, not its movement inside the plant.