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Center for Aquatic and Invasive Plants Logo    Plant Management in Florida Waters

Center for Aquatic and Invasive Plants Logo    Plant Management in Florida Waters


*Important: See Reference Guide Beforehand

No single herbicide is appropriate for controlling all invasive aquatic plants (or nuisance growths of native aquatic plants), in all situations. A herbicide may perform differently depending on the waterbody, its use, the time of year—or even the time of day. Therefore, aquatic plant managers must have a thorough understanding of how each herbicide acts in Florida aquatic systems. The following parameters are evaluated when considering this herbicide to manage aquatic plants in a specific waterbody. Each parameter is linked to an explanation and examples are provided to demonstrate their relevance to developing comprehensive aquatic plant management strategies.

Table A: Herbicide Use Patterns for Amine Endothall

Target PlantScientific NameUse PatternCompatible Herbicides
Crested floating heart Nymphoides cristata Occasional – most frequent use of amine endothall in FWC Program Alone or in combination with potassium endothall
Hydrilla Hydrilla verticillata Occasional – Spot applications Potassium endothall

Table B: Water Uses and Functions

Water Use ParametersManagement Considerations
Downstream Uses and Needs
  • Do not apply within 600 feet of functioning potable water intake
  • No irrigation restrictions listed for either formulation
Fish and Wildlife Mgmt.  
Vegetation planting
  • No issues related to this tool
Forage and prey
  • No issues related to this tool – potential for bioaccumulation is low
  • Highly toxic – blue gill, rainbow trout, channel catfish, daphnia EC50 > 0.36 ppm
  • Fish may be killed by doses in excess of 0.3 ppm
    • Use as small-scale or spot applications
    • Allow fish space to escape/avoid application site
Non-game wildlife
  • No issues related to this tool
Endangered species
  • No issues related to this tool at operational rates (0.05 – 0.3 ppm) and strategies
  • Non-toxic to waterfowl – mallard duck LD50 > 5,000 ppm
Flood Control
  • No issues related to this tool
Navigation and Access
  • No issues related to this tool
  • No irrigation restrictions
Livestock Consumption
  • No issues related to this tool for applications in Florida public waters
Potable Water
  • Apply 600 feet or greater from a functioning potable water intake
  • Coordinate applications with water facility operator
  • Public consumption of water only when the MCL is below 0.1 ppm
  • No issues related to this tool
  • No fish consumption restriction – does not bioaccumulate in fish
  • No issues related to this tool
  • No swimming restriction

Table C: Herbicide, Waterbody, Plant, and Climate Parameters

Herbicide ParametersManagement Considerations
Herbicide Rate
  • Applied at 0.05 – 0.3 ppm, often in combination with potassium endothall
    • Submersed or foliar applications for crested floating heart and hydrilla control
Breakdown / Inactivation
  • Half-life in water about one week or less
  • Microbial metabolism is primary degradation pathway
  • Does not adsorb to suspended solids or sediments
  • Does not degrade by photolysis
  • Not sensitive to hydrolysis
  • Breaks down fairly rapidly in water so dissipation is minimal
  • Available in liquid formulation
  • Available in granular formulation
Mechanism of Action
  • Unclassified in WSSA Resistance Grouping
    • Protein phosphatase inhibitor
Mode of Action  
  • Absorbed by foliage or underwater tissues
  • Interferes with protein and lipid synthesis
    • Disrupts cell membrane and respiration – cell membranes become leaky
    • Cell contents spill out – cannot make energy and die
  • Somewhat mobile in plant tissues
  • Long thought to be contact-type herbicide
    • Fast acting
Plant Growth Regulator
  • Not used as a plant growth regulator in Florida aquatic plant control applications
Herbicide resistance
  • Not yet classified in WSSA Resistance Grouping
  • No tolerance or resistance issues reported in Florida
    • Used occasionally with potassium endothall as a resistance management strategy
Waterbody ParametersManagement Considerations
Water depth
  • Used as submersed applications to control crested floating heart
    • Occasionally used for hydrilla or hygrophila control
  • Important to know water depth to calculate appropriate dose
Water volume
  • Used for crested floating heart control in small areas
    • Alone or in combination with potassium endothall
    • Volume of treated area is essential to calculate appropriate dose
Water movement
  • Need 12-24 hours of exposure for crested floating heart or hydrilla control
Water chemistry  
Dissolved oxygen (DO)
  • Generally, no issues related to this parameter
    • Control areas are typically small
    • Small amount of plant biomass controlled
pH, alkalinity, hardness
  • No issues related to this tool
Nutrient content
  • No issues related to this tool
    • Primarily used for small-scale crested floating heart control
Water transparency
  • Need actively growing plants for herbicide uptake
Sediment characteristics  
  • Sand / clay – no issues related to this tool
  • Organic – no issues related to this tool
Potential for re-suspension
  • Does not adsorb to suspended material
Plant Physiology ParametersManagement Considerations
Plant origin / growth potential  
  • Amine endothall is an algaecide
    • Infrequently permitted or used by FWC for this purpose in Florida waters
    • Little to no use with this compound for non-native vascular plant management
  • Little to no use with this compound for non-native plant management

  • Crested floating heart
    • Use alone or at low rates in conjunction with potassium endothall
    • Primary control method for crested floating heart
    • Follow-up applications may be necessary to control skips
      • Alone at 2 qt/acre-foot as subsurface injection
        • Apply to actively growing plants late summer (July – August)
      • Combination at 0.3 ppm with potassium endothall at 3.0 ppm
        • Apply late spring through summer
  • Hydrilla
    • Spot control new hydrilla infestations with granular formulation
      • Boat ramp / isolated spots in canals
Plant growth stage (target/non-target)
  • Need actively growing plants for herbicide uptake
Plant susceptibility (target/non-target)
  • Apply to actively growing target plants
    • May control vallisneria when used at higher rates with granular formulation
Potential for regrowth (target/non-target)
  • Hydrilla regrowth depends on extent of control, water clarity and depth
    • Regrowth is slower if root crowns are killed – limited to tuber / turion sprouting
    • Southern naiad and Illinois pondweed are controlled by endothall
      • Usually recover during the same or next growing season
Climate ParametersManagement Considerations
Weather Daily

  • Need at least 12-24 hours of contact exposure
  • Dependent on dose and water temperature
  • Windy conditions may increase dissipation in spot or band applications


  • Less herbicide may be required in cooler months
    • Microbial breakdown is slower so herbicide active for longer period
  • Applying to actively growing plants increases uptake
Light intensity
  • No issues related to this tool – not broken down by photolysis
Water temperature
  • Endothall degradation can occur more rapidly in warmer water (> 80°F)
    • Could result in reduced efficacy

Table D: Other Parameters

ParameterManagement Considerations
  • No generics or equivalent modes of action available
Anticipated Control Amount  
  • Area of control is generally confined to the area to which amine endothall is directly applied
  • Minimal dissipation and control may result outside of application zone
  • Control duration depends on dose, extent of contact, water clarity, and depth
  • If root crowns are killed, then regrowth is slower
    • Regrowth is from tubers / turions (hydrilla) or fragments / ramets (crested floating heart)
Time to Achieve Control
  • Symptoms in 5-7 days and control in 1-3 weeks
  • Usually applied via boat-mounted drop hoses as a tank mix with potassium endothall
  • Aerial applications are not conducted in Florida with this compound for aquatic plant control
  • Granular formulation applied with blower or spreader
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