Salvinia molesta Mitchell (Giant salvinia )

 


Ted D. Center,
USDA Agricultural Research Service, Bugwood.org

 

 

 

Family: Salviniaceae (Water Fern Family)

Synonym(s):

Duration: Annual, Perennial

Habit: Fern


Listed by:
Invasive Plant Atlas of the US: 1
Federal Noxious Weed: 1
TDA Noxious Weed: 1
TPWD Prohibited Exotic Species: 1

Description: Salvinia is a rootless, aquatic fern. Emergent groups of leaves (fronds), oblong and flat or semi-cupped, grow in chains and float on the water surface forming dense mats. Leaves grow in pairs and are approximately 1/2 inches wide and 1 inch long. A brown, thread-like leaf hangs underwater; all join at a node along a horizontal, underwater stem. The upper surface of the green leaves is covered with rows of white, coarse hairs, acting as a water repellent. The hairs of giant salvinia are joined at the tips in an egg beater shape.

History: Giant salvinia is a popular aquarium plant. It was first detected outside of aquarium and landscape cultivation in South Carolina in 1995, was found in Texas in 1997, and rapidly spread to other southern states over the following years.

Biology & Spread: While Salvinia may reproduce via spores as other ferns do, U.S. populations more commonly reproduce via budding from both attached nodes or broken stems. As many as five lateral buds can be found at one node. Populations can double every 2 weeks in the wild, and small quarter-acre ponds have been completely covered with giant salvinia in as little as 6 weeks from the point of invasion.

Ecological Threat: Dense mats of salvinia shade out native aquatic species and reduce dissolved oxygen levels in the water. Agricultural water use is impacted as salvinia obstructs intake pipes for irrigation. Recreational fishing and boating may be hindered by dense mats.

US Habitat: Salvinia thrives in slightly acidic, high nutrient, warm, slow-moving freshwater. Found in streams, lakes, ponds, ditches, and even rice fields. Resistant to periods of low temperature, dewatering, and elevated pH levels. Low tolerance to salinity.

Distribution

US Nativity: Introduced to U.S.

Native Origin: Brazil

US States: Texas, Louisiana, Mississippi, Alabama, South Carolina, North Carolina, Georgia, Florida, Arizona, California, Virginia, and Hawaii.

Resembles/Alternatives: American lotus (Nelumbo lutea), White water lily (Nymphaea odorata), Floating heart (Nymphoides aquatica).

Management: The best control is to prevent further infestations. Enclose harvested biomass and dispose in upland areas away from water. Herbicides (copper carbonate or Rodeo) are necessary for large populations. Biocontrol (Salvinia weevil) may also be effective.

USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS. MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.

Listing Source

Texas Department ofAgriculture Noxious Plant List
Texas Parks and Wildlife Department Prohibited Exotic Species
Invaders Program
Federal Noxious Weed
Union of Concerned Scientists
United States Forest Service Southern Research Station

Text References

The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area. Lisa Gonzalez and Jeff DallaRosa. Houston Advanced Research Center, 2006.

Data Source


Giant Salvinia News Roundup, Texas Parks & Wildlife.
Giant Salvinia in Texas Invasive Plant Database.

Last Updated: 2007-11-08 by LBJWFC