Submersed Weeds in Flowing Canals and Ditches

acrolein (Magnacide H)

Rate Up to 8 ppm

Time Apply when weed growth is no more than 4 to 6 inches tall.

Remarks Repeat treatments every 3 to 4 weeks during the remainder of the season.

Caution A restricted-use herbicide, due to its acute toxicity to humans. For retail sale to, and use by, certified applicators and only for those uses covered by the certified applicator's certification. Do not let humans or animals drink treated water. Toxic to fish and many other aquatic organisms. Special application equipment required. Use only oxygen-free nitrogen for a pressurizing agent. Following application, do not release treated water into any fish-bearing water, or area that might drain into fish-bearing water, until after the minimum waiting period defined on the appropriate label. Only labeled for use in irrigation canals.

Site of action General cell toxicant

Chemical family None generally recognized

dimethylamine salts of endothall (Hydrothol)

Rate 0.2 to 5 ppm in flowing water for 6 to 120 hr

Time Apply when submersed weeds are actively growing and interfering with water delivery.

Remarks Apply where water is slightly turbulent to facilitate mixing. Do not use treated water for any purpose within 7 to 25 days following treatment, depending on concentration applied. Not to exceed 5 ppm per application; maximum 30 ppm per growing season.

Caution Toxic to fish and wildlife. Fish may be killed at dosages above 0.3 ppm. Not for use in brackish/salt water. Minimum 600 ft setback from functioning potable water intakes. Do not use treated water for irrigation or agricultural sprays on food crops, watering livestock, or domestic purposes within 7 to 25 days following treatment, depending on concentration applied. Do not treat more than 1/10 of lake or pond at one time with concentrations higher than 1.0 ppm. Marginal or sectional treatments rather than an overall treatment is recommended.

Site of action Not well understood

Chemical family None generally recognized
In Washington, applicators using these herbicides in flowing canals or ditches water must ensure that their concentrations do not exceed those stated in the NPDES permit at the point of compliance.