Amine Endothall Considerations

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
HydrillaHydrilla verticillataOccasional/SpotLow rates in combination with potassium endothall
HygrophilaHygrophila polyspermaOccasionalLow rates in combination with potassium endothall
Crested floating heartNymphoides cristataOccasionalLow rates in combination with 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 liquid formulation of this compound
Fish and Wildlife Mgmt. 
Vegetation plantingNo issues related to this tool
Forage and preyNo issues related to this tool
Fisheries
  • Highly toxic - blue gill, rainbow trout, channel catfish, daphnia EC50 >1.00 ppm
  • Fish may be killed by doses in excess of 0.3 ppm
Non-game wildlifeNo issues related to this tool
Endangered speciesNo issues related to this tool at operational rates (0.05 – 0.3 ppm) and strategies
WaterfowlNon-toxic to waterfowl - mallard duck LD50 > 5,000 ppm
Flood ControlNo issues related to this tool
Navigation and AccessNo issues related to this tool
Irrigation
  • No issue related to this tool for established plants
  • Consult label for possible irrigation restrictions for newly seeded or transplanted plants
Livestock ConsumptionNo 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
Recreation 
BoatingNo issues related to this tool
FishingNo fish consumption restriction - does not bioaccumulate in fish
HuntingNo issues related to this tool
SwimmingNo swimming restriction

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

Herbicide ParametersManagement Considerations
Herbicide RateGenerally applied at 0.05 - 0.3 ppm in combination with potassium endothall for hydrilla control
Breakdown / InactivationHalf  life in water about one week or less
MicrobialMicrobial metabolism is  primary degradation pathway
Adsorption

Does not adsorb to suspended solids or sediments

Photodegradation

Does not degrade by photolysis

DissipationBreak down fairly rapidly in water so dissipation is minimal
Formulation 
Liquid
Solid
Mode of Action
 
Contact
  • Interferes with protein and lipid synthesis - disrupts cell membrane and respiration
  • Somewhat mobile in plant tissues
Plant Growth RegulatorNot used as a plant growth regulator in Florida aquatic plant control applications
Stewardship 
Herbicide resistance
  • No tolerance or resistance issues reported in Florida
  • Used occasionally with potassium endothall as a resistance management strategy
Waterbody Parameters Management Considerations
Hydrology 
Water depthImportant to know water depth to calculate appropriate dose
Water volumeGenerally used for hydrilla control in small areas in combination with potassium endothall - volume of treated area is essential to calculate appropriate dose
Water movementNeed at least 24 hours of exposure for hydrilla control
Water chemistry 
Dissolved oxygen (DO)Usually no issues related to this parameter since control areas are fairly small
pH, alkalinity, hardnessNo issues related to this tool
Nutrient content
No issues related to this tool - primarily used for small-scale hydrilla control
Water transparencyNeed actively growing plants for herbicide uptake
Sediment characteristics 
Composition  
  • Sand/Clay - no issues related to this tool
  • Organic - no issues related to this tool
Potential for resuspensionDoes not adsorb to suspended material
Plant Physiology Parameters Management Considerations
Plant origin/ growth potential 
NativeAmine endothall is an algaecide, but is infrequently permitted or used by FWC for this purpose alone in Florida waters
Non-nativeLittle to no use with this compound
Invasive  Occasionally  used at low rates in conjunction with potassium endothall to spot control new hydrilla infestations for example at boat ramps, or used with potassium endothall to control small areas of hydrilla as part of resistance management efforts
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 in combination with potassium endothall
Potential for regrowth (target/non-target)
  • Hydrilla regrowth depends on extent of control, water clarity and depth
    • Regrowth is slower if root crowns killed - limited to tuber/turion sprouting
  • Native plants southern naiad and Illinois pondweed are controlled by endothall, but usually recover during the same or next growing season
Climate Parameters Management Considerations
Weather
  • Daily
    • Need at least 24 hours of contact for hydrilla control
    • Dependant on dose and water temperature
    • Windy conditions may increase dissipation in spot or band applications
  • Seasonally
    • Less herbicide may be required in cooler months
    • Microbial breakdown is slower so herbicide active for longer period
    • Actively growing plants in late winter / early spring increases uptake
Light intensityNo issues related to this tool – not broken down by photolysis
Water temperatureEndothall degradation can occur more rapidly in warmer water (>80°) which could result in reduced efficacy

Table D: Other Parameters

ParameterManagement Considerations
CostNo generics available
Anticipated Control Amount 
SpatialArea of control is generally confined to the area to which endothall is directly applied – some dissipation and control may result outside of application zone
Duration
  • Control duration depends on dose, extent of control, water clarity, and depth
    • If hydrilla root crowns killed then regrowth is slower - from tubers/turions only
Time to Achieve ControlSymptoms in 5-7 days and control in 1-3 weeks
Contractor/Equipment
  • 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

Last updated: 23 October 2013