The Invasive Status of Giant Salvinia and Hydrilla in Mississippi

Giant salvinia (Salvinia molesta Mitchell) is a nuisance, free-floating aquatic fern that can double biomass in 10 days through vegetative reproduction. Hydrilla (Hydrilla verticillata (L.f.) Royle) is a perennial submersed aquatic plant that can propagate from stem fragments, turions, and subterranean tubers representing a triple threat for management methods. Both plants disrupt water bodies by affecting ecological interactions and halting boat traffic. Surveys were conducted during 200506 to detect the current status of giant salvinia and hydrilla in Mississippi. Giant salvinia was found at the Wedgeworth Creek located northeast of Leaf River near Petal in Forrest County. To date, giant salvinia has not escaped into the Leaf River. The biocontrol agent Cyrtobagous salviniae has been released at this site; however, no suppression and damage was noticed on the giant salvinia population. Hydrilla has been found in Lake Aberdeen, Aliceville Lake, Columbus Lake, Ross Barnett Reservoir, and Loakfoma Lake on the Noxubee National Wildlife Refuge (NWR). Management practices have been addressed for hydrilla control in the Ross Barnett Reservoir and Noxubee NWR. However, Lake Aberdeen, Aliceville Lake, and Columbus Lake are not currently under active management. Further surveys should be conducted to track giant salvinia and hydrilla spread over the reported sites as well as examine their presence in other of Mississippi water bodies.