Quick Facts

MORE INFO
Scientific name Hydrilla verticillata
Origin Southeast Asia
Introduction Early 1950s, aquarium trade
Aquatic community Submersed, surface mats
Habitat Inches to 35 feet deep
Distribution Statewide
Management effort Eradicate new infestations
Maintenance control of established plants
2017 public waters / plant acres 172 (37%) / 22,166
2017 Waters / acres controlled 105 / 26,502
Jeff Schardt (FWC) holding hydrillaHydrilla verticillata

Management Options
Biological Sterile grass carp stocked in about 100 public lakes; 4 host-specific insect species released with few successes; FWC is not currently funding overseas exploration for additional host-specific insects
Chemical Large-scale: potassium endothall, diquat, bispyribac, fluridone, penoxsulam; topramezone – small-scale: copper, diquat – research is focusing on combinations of herbicides, especially contact type herbicides with systemics
Mechanical Harvest from spring runs and boat trails in deep water, harvest or shred mats lodged against structures (bridges, dams)
Physical Hand pull / diver dredge new infestations, or in fast-flowing water

Environmental and Economic Concerns

  • Stems can elongate as much as 6-8 inches per day in Florida’s peak growing season
  • Can cover entire water body surface 1-2 years after introduction
  • 80% of plant mass is in the upper two feet of water column
    • blocks sunlight and shades out native plants
    • blocks air exchange and consumes oxygen, leading to fish kills
    • blocks access, navigation, and recreation
    • breaks loose and jams against bridges and dams
  • Reduces recreation-based incomes and property values
  • Doubles sedimentation rate from senescing leaves and stems
  • Disperses by fragments, buds, and runners (does not produce seeds)
  • Resists long-term control via underground propagules (tubers)
    • millions produced per acre
    • no effective tuber control method
    • viable tubers lie dormant for as long as seven years

DOWNLOAD
FWC Hydrilla Management Position (PDF)
FWC Hydrilla Management Position Background Information (PDF)

Florida Fish & Wildlife Conservation Commission, Status of the Aquatic Plant Maintenance Program in Florida Public Waters, Annual Report – Fiscal Year 2016-2017.