Floating Weeds in Lakes, Ponds, Irrigation Canals, and Drainage Ditches

diquat (Diquat Herbicide or Reward)

Rate 1 to 4 lb ai/A (0.5 to 2.0 gal per surface acre)

Time Apply when weeds are actively growing and water temperatures are above 50°F.

Remarks Add a registered nonionic surfactant when spot spraying at <0.5 gal per acre. Apply only to ponds and lakes with little or no outflow. Use diquat in waters that are totally under your control. In public waters, only federal or state public agencies, or contractors under their direct control, may use this product. Treat floating weeds by spot or broadcast treatments. Safe for fish at the rates given. There are no swimming or fishing restrictions for treated water.

Caution A moderately toxic herbicide that requires protective gear for handling and application. Do not allow spray to drift or come in contact with adjacent crops. Do not use treated water for domestic purposes, animal consumption, spraying, or irrigation for 1 to 5 days depending on water use and rate applied. Safe for fish at rates given. Do not let spray come in contact with skin, eyes, or clothing. Do not breathe spray mist.

Site of action Group 22: photosystem I electron diversion

Chemical family Bipyridilium

glyphosate (Rodeo, AquaNeat, AquaPro, AquaMaster, Cinco, Accord Concentrate and others)

Rate 0.75 to 3.75 lb ae/A (1.5 to 7.5 quart/A) applied as a broadcast spray or 0.75 to 2.0% solution in water applied through hand-held or high-volume equipment

Time Apply when weeds and brush are actively growing and most foliage is above the water surface.

Remarks See label for application rate and growth stage of weed and brush species. Floating mats of vegetation may require re-treatment. Add a surfactant labeled for use in water at the manufactures' surfactant label recommendations; surfactant must be at least 80% ai.

Caution Rain within 6 hours after application may reduce effectiveness. Do not apply within 0.5 miles upstream of potable water intakes. Apply to moving bodies of water only while traveling upstream. Do not overlap bank side applications more than 1 foot into open water. Do not exceed 3.75 lb ae/A in a single application being made over water. Take care to avoid drift to desirable plants. Do not spray where weeds do not exist.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

penoxsulam (Galleon SC)

Rate 2 to 5.6 fl oz/A with at least 10 GPA for aerial foliar applications and up to 100 GPA for ground foliar applications; for pre- or postemergent applications to exposed sediments, use 5.6 to 11.2 fI oz/A in a total spray volume of 20 to 100 GPA.

Time Apply only to actively growing weeds.

Remarks For postemergence foliar applications or treatments to exposed sediments, use with a surfactant approved for aquatic use (use with organosilicone surfactants not recommended). May be mixed with other herbicides or algaecides according to label specifications. Single applications should target minimum effective concentration of 25 to 75 ppb; split or multiple applications should target an initial dose of 10 to 30 ppb and subsequent applications to maintain that concentration for a minimum of 60 days (use ELISA or other analytical techniques to determine penoxsulam concentrations).

Caution Not for use in irrigation canals. Maximum target concentration in any treated area is 150 ppb ai per annual growth cycle. Do not apply Galleon SC through any type of irrigation system or use treated water for hydroponic farming, irrigating greenhouses or nursery plants; see label for other crop specific irrigation restrictions. Do not use in areas subject to rapid dilution.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Triazolopyrimidine