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Center For Aquatic And Invasive Plants

Center For Aquatic And Invasive Plants

Considerations


  • Labor intensive – may be limited to small areas – (for example, eradicate new invasive plant introduction)
  • Immediate control of small populations
  • Selective if water is clear and plants are readily distinguishable from intermixed, non-target plants
  • Long control duration – especially if roots are completely removed
  • Need suitable disposal area – preferably upland site close to control area
  • Use where other methods are not feasible or appropriate
    • Shallow water where harvesters cannot operate
    • Fast flowing waters where herbicide dose cannot be maintained near potable water intakes
    • Near endangered species habitat
  • Sediment type
    • Sediments may silt up control area and make locating plants difficult
    • Sand or clay sediments may make complete root removal difficult – quick recovery
  • Water depth
    • Easier to remove plants in less than 2-3 feet of water
    • Deep water may require SCUBA gear
  • Water clarity – plants must be easily seen for thorough control
  • Plant characteristics
    • May not be suitable for plants that fragment easily and whose fragments readily form new roots like hydrilla, Eurasian watermilfoil, or N. cristata
    • Difficult for plants with deep (American lotus), extensive (spatterdock), or easily fragmented (torpedograss) rhizomes

Examples of Feasible Control

  • Removing cattail or other emersed plants from around swimming areas, boat ramps or docks
  • Removing new infestations of invasive plants as part of eradication programs
    • Hand pick water hyacinth or water lettuce that drifts onto a shoreline
    • Pull emergsed Nymphoides cristata from small patches in lakes
    • Divers search for and pull up newly discovered hydrilla around boat ramps

Diver Assisted Dredging – A Variation of Hand Pulling

Facilitates hand pulling of plants especially in deeper water.

Considerations: Similar to Hand Pulling

  • Need specialized equipment including:
    • SCUBA gear
    • Barge and screening system to separate plants from sediments attached to roots
    • Pump and airlift / hose system
    • Spotter to assist diver safety and fend off boats, alligators, etc.
    • Deck attendants to remove dredged plants from screening apparatus
  • May cause temporary localized turbidity at control site and in screening area

Examples of Feasible Control

  • Deeper water in spring runs where herbicides and harvesting are not an option
  • Patrolling small areas to confirm eradication efforts for submersed invasive plants like hydrilla