Photographer: Charles T. Bryson Affiliation: USDA Agricultural Research Source:www.bugwood.org Copyright: CC BY 3.0
The common salvinia (Salvinia minima) is a small rootless, aquatic fern measuring about 1 inch in depth. The floating leaves are round and measure 1/2 inch to 3/4 inch in diameter, with a distinctive rib creating a bowl shaped appearance. The top of the leaf (on the water surface) often contains hairs with a single stalk that divides into four branches. Below the water surface leaves are modified to act as a root system for the plant. The common salvinia does not flower.
The common salvinia is an aggressive invader that forms dense mats, which prevent light from reaching native plant and fish species. The lack of light resources reduces dissolved oxygen levels in the water causing death and decay of native species. Agricultural water use is impacted as salvinia obstructs intake pipes for irrigation. Recreational fishing and boating is also prevented by dense salvinia growth.
The common salvinia reproduces via spores or fragmentation, which is consistent with other fern species. U.S. populations of common salvinia commonly reproduce via fragmentation from both attached nodes or broken stems. As many as five lateral buds can be found at one node. Rapid expansion has been recorded with populations doubling every 2 weeks in the wild. Small ponds have been completely covered with giant salvinia in as little as 6 weeks after invasion.
The introduction of common salvinia is believed to have occurred in the 1880's as a agricultural plant cultivated in greenhouses and gardens. It is believed to have become established via natural flooding of private ponds and pools in the 1920's in Florida. Currently, growth and distribution is only prohibited in Texas and Louisiana.
Habitat: Common salvinia thrives in slightly acidic, high nutrient, warm, slow-moving freshwater. It can be found in streams, lakes, ponds, ditches, and even rice fields. The common salvinia is resistant to periods of low temperature, dewatering, and elevated pH levels.
U.S. Present: AL, AZ, CA, FL, GA, HI, LA, MS, NC, SC, TX
American lotus (Nelumbo lutea), White water lily (Nymphaea odorata), Floating heart (Nymphoides aquatica)
The best control is to prevent further infestations. Enclose harvested biomass and dispose salvinias in upland areas away from water to prevent further establishment. Herbicides (copper carbonate or Rodeo) are necessary for treatment of large populations. Biological control using the Salvinia weevil may also be effective.
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Gonzalez, Lisa and Jeff DallaRosa. 2006. The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area. Houston Advanced Research Center.
Rayachhetry, M. B., T. R. Center, T. D. Center, P. Tipping, P. D. Pratt, and T. K. Van. 2002. First Report of the Pathogenicity of Rhizoctonia solani on Salvinia molesta and S. minima in Florida. Plant Diseases 86(7):813.
Tipping, Philip W., and T. D. Center. 2005. Population Dynamics of Cyrtobagous salviniae on Common Salvinia in South Florida. Journal of Aquatic Plant Management 43:47-50.
Tipping, P. W., Bauer, L., Martin, M. R., & Center, T. D. 2009. Competition between Salvinia minima and Spirodela polyrhiza mediated by nutrient levels and herbivory. Aquatic botany, 90(3):231-234.