2,4-D
Rate 2.5 to 6.2 gal/A-ft as concentrate
Time Apply when plants are actively growing (spring or early summer).
Remarks For use in quiescent or slow-moving waters; apply to moving bodies of water only while traveling upstream to prevent concentration downstream. No use restrictions for swimming, fishing, watering livestock or domestic purposes other than noted below.
Caution Limited to 2 applications per season; maximum of 10.8 lb ae/acre-foot per application; minimum 21 days between applications. Irrigation/spray use of water requires setback distance of 600 to 2,400 ft from functional water intakes, a waiting period of 21 days or approved assay of 2,4-D concentrations <100 ppb. Drinking water use requires setback distance from functioning water intakes of 600 to 2,400 ft, a waiting period of 21 days from application, or approved assay of 2,4-D concentrations < 70 ppb at water intake. See label for sampling requirements and posting requirements. To avoid oxygen depletion and potential fish kills, treat no more than half the waterbody at a time; for large infestations, leave buffer strips 100 ft wide and delay treatment of these for four to five weeks.
Site of action Group 4: synthetic auxin
Chemical family Phenoxy acetic acid
carfentrazone
Rate 0.05 to 0.2 lb ai/A
Time Apply in spring or early summer to actively growing weeds.
Remarks Inject into water with a boat-mounted injection system. Material may be applied as a surface spray only in combination with a suitable polymer or similar adjuvant that will ensure rapid sinking and mixing of the spray mix. Apply only to water with little or no outflow. Not registered for use in California.
Caution Moderately toxic to fish. Do not exceed 200 ppb in treated water. Do not apply within 1/4 mile of functioning potable water intakes in flowing or standing water. To avoid oxygen depletion and potential fish kills, treat no more than half the waterbody at a time; wait a minimum of 14 days before treating the remaining area. Water use restrictions of 0 to 14 days after treatment depending on percentage of water body treated and crop type. No restrictions to fishing and swimming. Consult label for specific water use restrictions.
Site of action Group 14: protoporphyrinogen oxidase inhibitor
Chemical family Triazinone
dipotassium salt of endothall
Rate 0.5 to 5 ppm for varying exposure times (see label for specifics by target weed)
Time Apply as early as possible after weeds appear and while actively growing.
Caution Toxic to fish and wildlife. Not for use in brackish/salt water. Minimum 600 ft setback from functioning potable water intakes. Do not use treated water for animal consumption or other domestic use within 7 to 25 days of treatment, depending on concentration applied. Not effective on elodea or chara. Treat areas with abundant growth of weeds in sections, and 5 to 7 days apart to avoid fish kill due to low oxygen level from decomposing weeds.
Site of action Group 31: currently thought to be a serine/threonine protein phosphatase inhibitor
Chemical family None generally recognized
diquat
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 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 submersed weeds using an invert emulsion applied by either subsurface or bottom applications (surface applications to treat dense submersed weeds or in depths over 2 feet is not recommended). Safe for fish at the rates given. This treatment is not effective on attached algae or chara. There are no swimming or fishing restrictions in treated water.
Caution A moderately toxic herbicide that requires protective gear for handling and application. Toxic to aquatic invertebrates. Do not use treated water for domestic purposes, animal consumption, spraying, or irrigating food crops for 1 to 5 days depending on water use and rate applied. Do not let spray contact skin, eyes, or clothing. Do not breathe spray mist. Do not use in turbid water. To avoid oxygen depletion and potential fish kills, treat no more than half the waterbody at a time; wait a minimum of 14 days before treating the remaining area.
Site of action Group 22: photosystem I electron diversion
Chemical family Bipyridilium
fluridone
Rate 30 to 150 ppb per treated surface acre; maximum application rate or sum of all application rates cannot exceed 150 ppb per annual growth cycle.
Time For best results, apply just before or just as weeds begin active growth.
Remarks Treat when water movement will be minimal. Results are best when fluridone contacts target plants for at least 45 days. Conduct an enzyme-linked immunosorbent assay test (ELISA) to determine the concentration of active ingredient in the water. Use an application pattern that gives uniform distribution; avoid concentrating the herbicide.
Caution Irrigating with treated water may injure crops. See label for irrigation times after application. Do not irrigate established tree crops for at least 7 days after application. Depending on formulation and application site, do not irrigate other crops for 7 to 30 days after application. May injure vegetation growing along shoreline. Do not apply at rates greater than 20 ppb within 0.25 miles of any functioning potable water intake.
Site of action Group 12: inhibits carotenoid biosynthesis
Chemical family None generally recognized
florpyrauxifen-benzyl
Rate For in-water applications, the maximum single application rate is approximately 48 ppb [5.0 or 25.0 Prescription Dose Units (PDU) depending on formulation] per acre-foot of water with a limit of three applications per year. Follow foliar application limits based on formulation.
Time For best results, apply to actively growing plants. However, effective control can be achieved over a broad range of growth stages and environmental conditions. Application to mature target plants may require higher application rates and longer exposure periods to achieve control.
Remarks Assumes treated area(s) have the potential to dilute with untreated water. If the treated area is not projected to dilute rapidly, utilize FasTEST to confirm below 2 ppb or verify vegetation tolerance before irrigation use. Consult a SePRO Aquatic Specialist for additional site-specific recommendations.
Caution See label for irrigation water use restrictions. Irrigating with treated water may injure crops. See label for irrigation times after application. Do not permit florpyrauxifen-benzyl EC formulation to come into contact during an application with any desirable broadleaf plants, as serious injury may occur.
Site of action Group 4: auxin herbicide chemotype
Chemical family Arylpicolinate
imazamox
Rate 50 to 500 ppb surface applied or injected
Time Apply early in the growing season.
Remarks Surface apply or inject into water column. Injection more effective on some species. Consult label. Apply to water with little or no flow. Repeat applications may be made, but do not apply at rates resulting in water concentrations greater than 500 ppb. There are no restrictions on use of treated water for livestock, swimming, fishing, agricultural spray or domestic use, as long as the setback restriction is observed (100 feet for irrigation intake; ¼ mile for potable water).
Caution Do not use treated water to irrigate greenhouses, nurseries, or hydroponics until water concentration is less than or equal to 1.0 ppb. Do not use treated water for other irrigation purposes less than 24 hr after application is completed, and only as long as concentrations in water are equal to or less than 50 ppb. When treating irrigation canals, the initial flush of recharge water after application must not be used for irrigation purposes. Note label restrictions on setback distances on applications to potable water intakes.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
penoxsulam
Rate 5 to 150 ppb
Time Apply only to actively growing weeds.
Remarks 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 (enzyme-linked immunosorbent assay test) or other analytical techniques to determine penoxsulam concentrations. For postemergence foliar applications or treatments to exposed sediments, use with a surfactant approved for aquatic use (use with organosilicone surfactants not recommended).
Caution 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 or actively flowing waters used for food-crop irrigation.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Triazolopyrimidine