Herbicides capable of destroying weed foliage via direct contact are classified as________________?
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Answer: B. Paraquet
Explanation
Paraquat is a fast-acting, non-selective contact herbicide that destroys green weed foliage upon direct application. It disrupts cellular membranes upon contact with sunlight, causing rapid desiccation of plant tissues. Because it only affects contacted tissue, it acts swiftly on annual weeds. Contact herbicides do not translocate significantly through the plant's vascular system to roots. Paraquat interferes with electron transport in photosynthesis, generating destructive reactive oxygen species. This chemical action causes visible wilting and browning within hours.
Farmers use paraquat for quick burndown weed control before crop emergence or in no-till farming systems. Its rapid action allows rapid planting schedules without leaving harmful soil residues. Due to high toxicity, its handling is strictly regulated in modern agriculture. Trifluration refers to a soil-incorporation herbicide application method rather than a contact herbicide. Bromoxynil and ioxynil are selective nitrile herbicides that behave differently than broad-spectrum contact herbicides.
- Subject
- Agriculture
- Category
- Agriculture
- Topic
- —
- Difficulty
- medium
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