| Herbicide Rate | - Generally applied at 2quarts imazapyr + 7.5 pints glyphosate / acre
- Do not apply more than 6 pints per acre per year
- Must be applied with spray adjuvant
- Non-ionic or silicone surfactant, methylated seed or vegetable oil, or invert emulsion
|
| Breakdown / Inactivation | Half life in water about 2 days - much greater on terrestrial soils (1-5 months) |
| Adsorption | In soils, slow microbial metabolism is primary degradation pathway |
| Microbial | Adsorbs to soil at pH<5 - more mobile and available to plants in soil >pH5 |
| Photolysis | Rapidly degrades by photohydrolysis in water |
| Dissipation | - Not used for submersed plant control so not applied directly to water
- May persist longer and therefore be more mobile in soils >pH5
|
| Formulation | |
| Liquid | Available in liquid formulation only |
| Solid | Not available in solid formulation |
Mode of Action
| |
| Systemic | - Foliar application - translocates in xylem and phloem to meristematic tissue
- Prevents synthesis of branched-chain amino acids
- May be exuded from roots and control plants with intermixed root systems
|
| Plant Growth Regulator | Not used as a plant growth regulator in Florida aquatic plant control applications |
| Stewardship | |
| Herbicide resistance | - No tolerance or resistance issues reported in Florida
- Rotate or use with glyphosate where appropriate
|
| Waterbody Parameters | Management Considerations |
| Hydrology | |
Water depth
| No issues related to this tool, not used for submersed plant control |
| Water volume | No issues related to this tool, not used for submersed plant control |
| Water movement | No issues related to this tool, not used for submersed plant control |
| Water chemistry | |
| Dissolved oxygen (DO) | - No issues related to this tool, not used for submersed plant control
- Fairly slow acting herbicide used for shoreline applications and within secluded marshes where DO is less concern
|
| Alkalinity, ph, hardness | May be more mobile when controlling torpedograss on non-aquatic soils >pH 5 |
Nutrient content
| - No issues related to this tool, not used for submersed plant control
- Fairly slow acting herbicide used for shoreline applications and within secluded marshes
|
| Water transparency | No issues related to this tool, not used for submersed plant control |
| Sediment characteristics | |
Composition
| - Sand/Clay – no issues related to this tool
- Organic – no issues related to this tool
|
| Potential impacts from sediment resuspension | - No issues related to this tool
- Not used for submersed plant application
- Does not readily adsorb to suspended material in tank mix water
|
| Plant Physiology Parameters | Management Considerations |
| Plant origin/ growth potential | |
| Native | Occasional use to control cattail |
| Non-native | Occasional use to control alligatorweed, tropical American water grass |
| Invasive | - Frequent use to control torpedograss away from irrigation water intakes
- Occasional use to control West Indian marsh grass
|
| Plant growth stage (target/non-target) | - Need actively growing plants for herbicide uptake
- Same rates must be applied to control young or mature plant growth
|
Plant susceptibility (target/non-target)
| - Apply to actively growing target plants
- Fairly broad spectrum herbicide will control most annual and perennial grasses and broadleaf plants
|
| Potential for regrowth (target/non-target) | - Generally 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
|
| Climate Parameters | Management Considerations |
| Weather | |
| Daily considerations | - Rainfast one hour after application
- Non-target damage due to drift is a concern
- Best applied in winds between 3-10 mph
- Avoid applications in winds below 3 mph - variable wind or temperature inversion may exist
|
| Seasonal | Selectivity is increased if torpedograss is controlled in winter when non-target plants like buttonbush are dormant |
| Light intensity | No issues related to this tool |
| Water temperature | No issues related to this tool |
