Hydrilla

Quick Facts

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 Maintenance control
2013 public waters / plant acres:

187 / 28,610

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)

Hydrilla verticillata
Hydrilla verticillata
Jeff Schardt (FWC) holding hydrilla
Jeff Schardt (FWC) holding hydrilla

Management Options

 
Biological Sterile grass carp; host-specific insects (few insect successes to date); testing a pathogen in conjunction with herbicides; overseas exploration continues for additional host-specific insects
Chemical Large-scale: endothall, bispyribac, flumioxazin, fluridone, imazamox, penoxsulam; topramezone - small-scale: copper, diquat; and combinations of herbicides
Mechanical Harvest from spring runs and boat trails in deep water, harvest / shred mats lodged against structures (bridges, dams)
Physical Hand pull / diver dredge new infestations, or in fast-flowing water

Florida Fish & Wildlife Conservation Commission, Status of the Aquatic Plant Maintenance Program in Florida Public Waters, Annual Report – Fiscal Year 2009-2010.

Last updated: 12 August 2014