Which statement describes the endothall mode of action and target plants?

• A. It is a broad-spectrum, contact herbicide effective against submerged aquatic plants.
• B. It is a systemic herbicide absorbed by roots.
• C. It only affects flowering aquatic plants.
• D. It is a soil-applied residual herbicide.

Answer: (A)

Endothall is a contact herbicide used in aquatic weed control; it acts on the tissues it touches rather than moving systemically through the plant. This means it must physically contact the target plant tissues in the water to be effective, causing rapid tissue damage and death where it contacts. In practice, endothall is used for submerged aquatic plants, making it broad in its activity against many common submersed weeds. The statement that best describes its action and targets is that it is a broad-spectrum, contact herbicide effective against submerged aquatic plants. It is not absorbed and moved through the plant to a distant site (not systemic), it isn’t a soil-applied residual product, and its effects aren’t limited only to flowering aquatic plants.