Family: Salviniaceae (Water Fern Family)
Duration and Habit: Annual, Perennial Fern
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. Hairs of common salvinia are unjoined at the tips. Fruits (sporocarps) are egg-shaped and grow in chains underwater.
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.
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.
History: Common salvinia was long considered to be native to the U.S. However, it was most likely introduced to the US in the 1920s.
U.S. 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.
U.S. Nativity: Introduced to U.S.
Native Origin: Mexico, So. Amer (Germplasm Resources Information Network); NatureServe Explorer
U.S. Present: AL, FL, GA, LA, MA, MD, NM, NY, OK, PR, SC, TX
List All Observations of Salvinia minima reported by Citizen Scientists
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 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.
The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area. Lisa Gonzalez and Jeff DallaRosa. Houston Advanced Research Center, 2006.
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