• See irrigation and potable water parameters below

• Avoid applications within or near newly planted aquatic revegetation sites

• No issues related to this tool

• No fishing or fish consumption restrictions

• No issues related to this tool

• No issues related to this tool

• No issues related to this tool

• No issues related to this tool

• No issues related to this tool

• Rate dependent water use restrictions – see label for specific information
  • < 10 ppb concentration in treated water – no precautions for established tree, row crops, or turf
  • > 5 ppb – do not irrigate tobacco, tomatoes, peppers and newly seeded crops or grass

• No water use restriction

• No restrictions when applying fluridone at < 20 ppb
• Do not apply at concentration > 20 ppb within 1/4 mile from functioning potable water intake
• Coordinate applications within 1/4 mile of an active potable water intake with water facility manager

• No issues related to this tool

• Fishing – no fishing restriction – little to no bioaccumulation in fish

• No issues related to this tool

• No swimming restrictions

• Generally applied for hydrilla control at concentration in water of 5-20 ppb
  • Label allows rates up 150 ppb
  • Water and crop tolerance established by EPA at 150 ppb
• Hydrilla exhibits different levels of susceptibility to fluridone in Florida public waters
  • Conduct genetic test to determine effective rate needed for each waterbody

• Half-life in water of 20 days or more
  • Varies with light intensity
  • Half-life longer in clay or organic sediments

• Broken down microbially – lesser pathway
  • Some areas experience enhanced microbial breakdown
    • After repeated use of fluridone
    • Half-life may be as little as 7-10 days
  • Too short to sustain concentration for cost-effective hydrilla control

• Mildly binds to clay and organic particles

• Broken down by sunlight – primary pathway

• Not sensitive to hydrolysis

• May disperse widely throughout treated waterbody due to long half-life

• Available in liquid / aqueous formulation

• Available in various clay pellet formulations
  • Reported rates of 7-30 days for peak release of herbicide from pellet
  • Release is generally faster in sandy soils
  • Release is generally faster in flowing water
• Quick-release pellets applied directly to root zone of non-target eel grass (Vallisneria americana) may have unintended impacts

• Classified in WSSA Resistance Grouping #12
  • Carotenoid Biosynthesis Inhibitors

• Absorbed only by underwater tissues
  • Does not move within the plant, but is not a contact-type herbicide
• Inhibits phytoene desaturase, which leads to decreased levels of carotenes
  • Carotenoids are chlorophyll protecting pigments
  • Unprotected chlorophyll photo-oxidizes leading to plant starvation
  • Eventually leads to decreases in chlorophylls, photosynthesis, and carbohydrate stores
    • Symptoms include bleached, white tissue, sometimes pinkish
  • Slow acting – concentration must be maintained from 60-90 days or more

• Has been applied as a plant growth regulator in Florida waters
• Low dose fall applications (5ppb) suppress tuber and turion production in hydrilla

• Resistance confirmed in hydrilla in Florida
  • Repeated use killed susceptible clones and selected for less susceptible biotypes
• Conduct genetic test prior to application to determine susceptibility of current hydrilla population
• Rotate other compounds for subsequent hydrilla control operations or
• Use in combination with another herbicide active ingredient

• Important to target and maintain prescribed dose
• Accurate bathymetry is imperative for hydrilla and other submersed plant control

• Important to target and maintain prescribed dose
• Accurate bathymetry is imperative for hydrilla and other submersed plant control

• Maintaining a prescribed dose 60-90 days or more may be required for submersed plant control
  • Shorter for young actively growing plants – longer for mature, robust plants

• Very slow acting for hydrilla control
  • Dissolved oxygen sags are usually not an issue

• No issues related to this tool

• Slow acting – nutrients released from dying plants over extended period, therefore, no issue

• No issues related to this tool

• Sand/Clay – slight absorption in deep flocculent clay sediments
• Organic –slight absorption to suspended organic particles

• No issues related to this tool

• Not used to control native plants in FWC-funded program

• Not used to control non-native plants in FWC-funded program

• Occasionally used to control susceptible hydrilla
• Used in waters in which recent genetic test shows hydrilla susceptibility from 3-15 ppb
• Monitoring using HPLC or other acceptable method during fluridone exposure period to confirm correct concentration is sustained
• May require multiple applications to target area to sustain prescribed concentration up to 90 days
• Sustain prescribed concentration until visual observations confirm that hydrilla will not recover
• Used in combination with contact-type herbicides (primarily potassium endothall)
  • Control with fluridone – follow up control of surviving hydrilla with potassium endothall
  • Control with contact-type herbicide to reduce biomass – manage regrowth with fluridone
  • Combine with systemic herbicide (primarily penoxsulam)
  • Reducing rates of each herbicide increases selectivity

• Shorter exposure periods may be applicable for young actively growing plants

• Resistance confirmed in hydrilla
• Cost-effective/selective control of hydrilla that is genetically confirmed as susceptible at 3-15 ppb
  • Apply to actively growing target plants
• Selectivity varies widely depending on:
  • Growth stage
    • Surface matted hydrilla is more difficult to control
    • Slower growth rate, so lower herbicide uptake
    • Mature hydrilla is more difficult to control due to higher carbohydrate reserves
  • Herbicide dose
    • Test for and monitor to maintain the lowest effective dose for hydrilla control
    • Spatterdock (Nuphar lutea) and pondweeds (Potamogeton spp.) are susceptible to fluridone at most rates applied to control hydrilla – expect injury
  • Formulation
    • Pellets may allow for longer exposure of herbicide
    • Release herbicide through time
    • Avoid applying pellets at high rates directly to roots of eelgrass (Vallisneria americana)
  • Time of year
    • Native plants are generally dormant during fall and winter applications
      • Hydrilla may be actively growing
      • Increasing selectivity

• Provides long-term control of susceptible hydrilla – up to 12-18 months
• Lengthy exposure results in death of standing crop
  • Also controls sprouting tubers for several months
• Low dose inhibits tuber and turion production during fall/winter applications

• Avoid applications during high wind and wave conditions to minimize herbicide dispersal

Seasonally

• Hydrilla control efficacy and selectivity is greatest for fall, winter, early spring applications
• Shorter winter daylight period reduces herbicide photolysis
  • Leads to extended fluridone half-life

• Photolysis is primary degradation pathway
• Increased light intensity leads to shorter half-life

• Avoid application of aqueous formulation if strong thermocline exists

• Generics are available
• Relatively high fluridone cost per pound of active ingredient is mitigated through:
  • Low use rates, long-term control, and high ratio of acres controlled vs. acres treated
• Other herbicides are available for rotation or combination

• Slow action systemic herbicide generally disperses widely outside treatment area
• Acres of hydrilla controlled can exceed acres of plants to which herbicide is directly applied

• Controls susceptible hydrilla up to 12-18 months

• Slow acting – hydrilla must be exposed to appropriate fluridone concentration for 60-90 days

• Apply by boat or aerially by helicopter for larger acreages of submersed plants
• Apply by hoses trailing from boat for submersed plant control
• Laboratory analysis must be available to:
  • Determine hydrilla susceptibility prior to application
  • Monitor fluridone concentration in water to sustain prescribed concentration