• Systemic herbicide that requires 60-90 days of exposure for control
• Apply to waters with limited to no outflow to avoid downstream, off-target control

• Avoid whole-lake or large block applications adjacent to recently planted susceptible plants
  • Especially soft-stem bulrush (Schoenoplectus tabernaemontani) and jointed spikerush (Eleocharis interstincta)

• No issues related to this tool – potential for bioaccumulation is low

• Practically non-toxic – blue gill and rainbow trout LC₅₀ >100 ppm

• No issues related to this tool

• No issues related to this tool at operational rates (30-45 ppb) and strategies

• Practically non-toxic – mallard duck, bobwhite quail LC₅₀ >5,620 mg/kg

• No issues related to this tool

• No issues related to this tool

• Do not use treated water to irrigate food or ornamental crops until the bispyribac level in the treated water is determined to be 1.0 ppb or less

• Treated water may not be used as a primary water source for livestock until the bispyribac level in the treated water is determined to be 1.0 ppb or less

• No drinking water restrictions

• No issues related to this tool

• No fish consumption restriction – does not bioaccumulate in fish

• No issues related to this tool

• No swimming restriction

• Subsurface injection to control hydrilla at 30-45 ppb
• Need 60-90 days exposure for hydrilla control

• Half-life in water about 30 days
• Requires 1-2 reapplications to maintain prescribed dose for 60-90 days

• Microbial metabolism is primary degradation pathway

• Does not bind or adsorb to soil particles

• Not sensitive to photolysis

• Not sensitive to hydrolysis

• Do not apply to flowing water or to waters subject to rapid dissipation
• Apply to entire waterbody or large-block application
  • Will dissipate from narrow band or small plot applications before control achieved

• Not available in liquid formulation

• Available as water-soluble powder – mix with water and apply as solution

• Classified in WSSA Resistance Grouping #2
  • Amino Acid Biosynthesis Inhibitor (blocks ALS enzyme)

• Absorbed by foliar tissues and moves to areas of new growth
• Prevents formation of essential branched chain amino acids in plants (ALS)
• Plant cannot make proteins, enzymes, etc. and eventually starves and dies

• Not used as a plant growth regulator in Florida aquatic plant control applications

• Classified in WSSA Resistance Grouping #2
• Resistance to ALS compounds confirmed in terrestrial species
• No tolerance or resistance issues reported for bispyribac in Florida
• Used occasionally with potassium endothall as a resistance management strategy
• Rotate / alternate other compounds for successive large-scale hydrilla applications

• Important to know water depth to calculate appropriate concentration

• Important to have accurate bathymetry to calculate appropriate concentration

• Do not apply into flowing waters or waters subject to rapid dilution or dissipation

• Fairly slow acting herbicide taking two months or more to achieve hydrilla control
  • Oxygen depletion due to rapid kill and decomposition is not likely

• No issues related to this tool

• Slow acting herbicide taking two months or more to achieve hydrilla control
  • Rapid nutrient release and subsequent algae blooms not likely

• Not broken down by photolysis
• Clearer water may accelerate plant growth, increasing uptake and control efficacy

• Not bound to clays
  • May give better control in sand bottom lakes vs. organic sediments

• No issues related to this tool
  • Does not adsorb to suspended material in water body or in tank mix water

• Not used to target native plants in FWC Programs

• Not used to target non-native plants in FWC Programs

• Subsurface injection to control hydrilla at 30-45 ppb
  • Maintain concentration for 60-90 days
• Apply 30 ppb + 1 ppm potassium endothall for hydrilla control
• Apply to entire waterbody or large block application

• Need actively growing plants for herbicide uptake
• For best results, apply in late winter / early spring before hydrilla matures

• Current use in Florida is for hydrilla control (occasionally Cabomba caroliniana)
• More effective on immature and actively growing hydrilla
• Higher rates or applications with potassium endothall may impact eel grass
• Little to no impact on southern naiad (Najas guadalupensis) and pondweeds (Potamogeton spp.)
• Spatter-dock (Nuphar spp.) and jointed spikerush may be susceptible

• Longer term control when applied to actively growing immature hydrilla
• Temporary injury reported for soft-stem bulrush in greenhouse studies

• Apply in relatively calm water when little to no flushing is anticipated

Seasonally

• Apply in late winter / early spring
  • When hydrilla is actively growing
  • Lower carbohydrate reserves so control may be more thorough
  • Native plants may be dormant or less susceptible
  • Summer flushing rainfalls are less likely
  • Microbial breakdown activity is reduced
• Applying to actively growing plants increases uptake

• Not broken down by photolysis
• Higher light intensity may equate to rapid plant growth and herbicide uptake

• No issues related to this tool

• No generics available
• Herbicides with equivalent mechanisms of action are available

• Apply to entire waterbody or large blocks of hydrilla
• Control will likely extend beyond area to which bispyribac is directly applied

• Better efficacy during cooler weather – late winter or early spring
• More herbicide uptake in actively growing hydrilla – more thorough control
• If root crowns are controlled, regrowth is only from tubers or turions

• Slow-acting systemic – may take two or more months to control target plants

• Wettable powder must be mixed and applied as solution
• Apply via subsurface injections by boat
• Conduct water analysis 2-3 weeks and redoes as needed to sustain prescribed dose