• Extensive (120-day) irrigation label restriction limits imazapyr use in FWC management programs
  • Applied mostly within the marshes of Lake Okeechobee and TM Goodwin / Broadmoor Marsh
• Care taken when deciding to apply near desirable trees as residual soil activity is possible

• Broad spectrum herbicide for emergent and floating plants
• Do not apply immediately adjacent to desirable emergent plants
• No activity on submersed plants

• No issues related to this tool

• Low toxicity 96hr LC₅₀
  • Bluegill = 148 mg/L
  • Rainbow trout = 117 mg/L
  • Daphnia = 132 mg/L

• No issues related to this tool

• No issues related to this tool

• Non-toxic to waterfowl
  • Mallard duck LD₅₀ > 5,000 ppm

• No issues related to this tool

• No issues related to this tool

• Do not apply within 1 mile of active irrigation water intake
  • 1/2 mile downstream of active intake in flowing water
• Do not use treated water for irrigation for 120 days after application or
  • Until residue levels from laboratory analysis fall below 1.0 ppb
• Do not irrigate for at least 24 hours following application to allow for dissipation

• No issues related to this tool

• Do not apply within 1/2 mile upstream of a functioning potable water intake
• Do not apply within 1/2 mile of an active potable water intake in a standing body of water
• Applications within 1/2 mile of potable water intake can be made if:
  • The intake is shut down for a minimum of 48 hours
  • Coordinate applications with water facility operator

• No issues related to this tool

• No fish consumption restriction
  • Does not bioaccumulate in fish

• No issues related to this tool

• No swimming restriction

• Max rate = 1.5 lb ae (96 fl oz) / ac / yr
• Generally applied at 64 oz imazapyr + 96 oz glyphosate / acre for invasive grass control
• Must be applied with spray adjuvant
  • Non-ionic or silicone surfactant
  • Methylated seed or vegetable oil

• Half-life in water about 2 days
  • Much greater on terrestrial soils (1-5 months)

• In soils, slow microbial metabolism is primary degradation pathway

• Adsorbs to soil at < pH5
• More mobile and available to plants in soil > pH5

• Rapidly degrades by photolysis in water
  • Degrades faster in spring and summer

• Not sensitive to hydrolysis

• Not used for submersed plant control so not applied directly to water
• May persist longer and therefore be more mobile in soils > pH5

• Available in liquid formulation only

• Available in liquid formulation only

• Classified in WSSA Resistance Grouping #2
  • Acetolactate synthase (ALS) enzyme inhibitor

• Quickly absorbed by leaves and shoots
• Moves to areas of new growth
• Shuts down plant growth almost immediately
  • Acts like contact herbicide in this regard
  • Control may take 2-6 weeks
• Prevents the formation of essential branched chain amino acids in plants – ALS
  • Without these essential amino acids, the plant cannot make proteins, enzymes, etc.
  • Plant cannot continue growing and eventually starves and dies
• May be exuded from roots and control plants with intermixed root systems

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

• Resistance to ALS compounds confirmed in terrestrial species
  • No resistance reported in Florida aquatic plants
• Rotate or combine with glyphosate where appropriate

• No issues related to this tool, not used for submersed plant control

• No issues related to this tool, not used for submersed plant control

• No issues related to this tool, not used for submersed plant control

• No issues related to this tool, not used for submersed plant control
• Slow acting herbicide
• Used for shoreline applications or within secluded marshes where DO is less concern

• May be more mobile when controlling torpedograss on non-aquatic soils > pH 5

• No issues related to this tool, not used for submersed plant control
• Slow acting herbicide used for shoreline applications and within secluded marshes

• No issues related to this tool, not used for submersed plant control

• Sand/Clay – no issues related to this tool
• Organic – no issues related to this tool

• No issues related to this tool
  • Not used for submersed plant application
  • Does not readily adsorb to suspended material in tank mix water

• Cattail and tussocks
  • Apply imazapyr at 64 oz / ac to control cattail or mixed herbaceous and woody tussocks
  • Most often applied in TM Goodwin Waterfowl Management Area (WMA)

• Occasional spot applications on non-native plants

• Torpedograss, paragrass, Cuban club-rush, Tropical American watergrass
  • Apply imazapyr at 64 oz /ac or
  • Apply imazapyr at 16 oz /ac + 96 oz / ac glyphosate
  • Most often applied within Lake Okeechobee levee or TM Goodwin WMA
    • Imazapyr and imazapyr + glyphosate are relatively non-selective
    • Used to control most invasive grass and woody species to improve waterfowl habitat

• Need actively growing plants for herbicide uptake
• Same rates must be applied to control young or mature plant growth

• Apply to actively growing target plants
• Broad spectrum herbicide will control most annual and perennial grasses and broadleaf plants

• Up to 2-5 years of torpedograss control allowing other species to colonize
• Sagittaria and water lily species usually recover from seed bank in areas where dense torpedograss is controlled

• Rainfast one hour after application
• Non-target damage due to drift is a concern
  • Best applied in winds between 3-10 mph
  • Caution in winds below 3 mph – variable wind or temperature inversion may exist

Seasonally

• Selectivity is increased if torpedograss is controlled in winter
  • When non-target plants (e.g. buttonbush) are dormant

• No issues related to this tool

• No issues related to this tool

• Generics available

• Area of control is generally confined to the area to which imazapyr is directly applied to target emergent or floating plants

• 2-5 years of control reported for torpedograss and cattail
• Regrowth usually from incomplete control of extensive underground rhizomes, from existing seed bank, or pioneering plants

• Symptoms in 2 or more weeks
• Complete kill in several weeks after application

• Foliar applications by backpack for spot control
• Airboat or ATV for moderate-scale applications
• Helicopter for large-scale application