- Latin Name: Salvinia molesta
- Latin Family Name: Salviniaceae
- Common Name: Giant Salvinia
- Other Names: Kariba weed
Origin:
Native to southeastern Brazil, it is now an invasive species all throughout the United States and Europe.
Biology:
It reproduces by asexual reproduction only, but it is capable of growing extremely quickly, starting from small fragments and doubling in dry weight every 2–3 days. It grows from fragments that have broken off or dormant buds that have been detached from the main plant. Each node has five buds. It also produces spores, but they are genetically defective and do not produce viable offspring.
Identification:
It is a free-floating plant that does not attach to the soil, remaining buoyant on the surface of a body of water. The fronds are 0.2-1.5" long and broad, with a bristly surface caused by the hair-like strands that join at the end to form eggbeater shapes. They are used to provide a waterproof covering. These fronds are produced in pairs also with a third modified root-like frond that hangs in the water. Under the best conditions, plants can form a 2-foot-thick mat.
Characteristics Important to Control:
Cyrtobagous salviniae is a weevil that has been shown to be effective at eating the root and killing the plant. The giant gourami is a fish that is also effective at feeding on the plant to control it. Harvesting the plant manually is only effective at controlling small infestations. Once removed, the plant needs to be dried, burnt, or disposed off in another manner that ensures it will not re-enter the water. The plant has resistance to some herbicides, but using a combination of hexazinone, diquat, and double-chelated copper has been proven effective at controlling the plant.
