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Giant Salvinia

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Giant salvinia
Scientific Name:

Salvinia molesta D. S. Mitch. (ITIS)

Common Name:

Giant salvinia, kariba-weed

Giant salvinia, plants - Photo by Scott Bauer; USDA, Agricultural Research Service


  • USDA. ARS. Tellus.

    In parts of the South, there are stories about an invasive floating weed, which forms such a dense mass that it enables small animals to walk across water. This weed, called giant salvinia, is an exotic fern from South America that invades ponds, lakes, and other waterways in the United States. It damages aquatic ecosystems by outgrowing and replacing native plants that provide food and habitat for native animals and waterfowl.

    Agricultural Research Service (ARS) scientists are testing a naturally occurring fungus (Myrothecium spp.) against giant salvinia to help control it. Initial tests have found that the fungus stops this problematic weed from growing and even can kill it.

Native To:
Date of U.S. Introduction:
Means of Introduction:

Horticultural trade (McFarland et al. 2004)


Forms dense mats that block sunlight and reduce oxygen levels (McFarland et al. 2004)

Distribution/Maps/Survey Status

Federally Regulated

  • USDA. APHIS. Plant Protection and Quarantine.

    Includes species listed as a Federal Noxious Weed under the Plant Protection Act, which makes it illegal in the U.S. to import or transport between States without a permit.



Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Giant Salvinia.

Council or Task Force

Aquatic Nuisance Species Task Force.


European and Mediterranean Plant Protection Organization.

USDA. APHIS. PPQ. Center for Plant Health Science and Technology; California Department of Food and Agriculture.

IUCN. Species Survival Commission. Invasive Species Specialist Group.
University of Georgia. Center for Invasive Species and Ecosystem Health.
East African Network for Taxonomy.
USDA. FS. Institute of Pacific Islands Forestry.

Texas Commission on Environmental Quality, Galveston Bay Estuary Program; Houston Advanced Research Center (HARC).

Federal Government

DOI. USGS. Wetland and Aquatic Research Center.
Provides distribution maps and collection information (State and County).
USDA. NRCS. National Plant Data Center.
USDA. ARS. National Genetic Resources Program. GRIN-Global.

International Government

New South Wales Department of Primary Industries (Australia).
Australian Government. Department of the Environment and Energy.
Cooperative Research Centre for Australian Weed Management.

State and Local Government

California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources

Wisconsin Department of Natural Resources.

South Carolina Department of Natural Resources. Aquatic Nuisance Species Program.
Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.
Florida Fish and Wildlife Conservation Commission.


University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets
Texas A&M University. AgriLife Extension Service. Department of Wildlife and Fisheries Sciences.

University of Florida. IFAS. Center for Aquatic and Invasive Plants.


Colorado Weed Management Association.