Center For Aquatic And Invasive Plants

Amine Endothall Considerations

*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.

These considerations are not meant to replace or contradict the EPA approved label.
Always read and follow the pesticide label for each product used.

Table A: Herbicide Use Patterns for Amine Endothall

Target Plant	Scientific Name	Use Pattern	Compatible 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 Parameters	Management 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
Fisheries	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
Waterfowl	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
Irrigation	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
Recreation
Boating	No issues related to this tool
Fishing	No fish consumption restriction – does not bioaccumulate in fish
Hunting	No issues related to this tool
Swimming	No swimming restriction

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

Herbicide Parameters	Management 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	Microbial metabolism is primary degradation pathway
Adsorption	Does not adsorb to suspended solids or sediments
Photolysis	Does not degrade by photolysis
Hydrolysis	Not sensitive to hydrolysis
Dissipation	Breaks down fairly rapidly in water so dissipation is minimal
Formulation
Liquid	Available in liquid formulation
Solid	Available in granular formulation
Mechanism of Action	Unclassified in WSSA Resistance Grouping Protein phosphatase inhibitor
Mode of Action
Systemic	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
Stewardship
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 Parameters	Management Considerations
Hydrology
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
Composition	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 Parameters	Management Considerations
Plant origin / growth potential
Native	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
Non-native	Little to no use with this compound for non-native plant management
Invasive	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 Parameters	Management 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 Seasonally 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

Parameter	Management Considerations
Cost	No generics or equivalent modes of action available
Anticipated Control Amount
Spatial	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
Duration	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
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 or spreader