text: Biological control A tiny weevil, Cyrtobagous salviniae, found in the native distribution of S. molesta, is being studied as a biocontrol. C. salvinae was first used as a biological control in Australia at Lake Moondarra, a recreational lake in Mount Isa, Queensland in 1980. By mid-1981, the weevil had reduced the population to a few small patches. It ate the leaves of the weed, but preferred the buds. Its larvae ate the roots, rhizomes, and the buds. As the plant died, it turned brown and sank to the bottom of the waterway and decomposed. This weevil was used with success in other parts of the world (13 tropical countries) such as the Sepik River in Papua, Sri Lanka, Lake Ossa in Cameroon as part of an AMMCO project to restore African manatee; Wappa Dam in Queensland, and lagoons (e.g. Kakadu National Park) in the Northern Territory, Australia. In Australia, the moth, Samea multiplicalis was also released in the hopes that it would reduce the size of the weed population. While this moth did become established in Australia and spread, it was not effective as a biological control. A third species, the grasshopper Paulinia acuminata, was considered, but not released in Australia. However, this grasshopper has been deliberately released for control of Salvinia molesta in parts of Africa, Sri Lanka and India, and accidentally in Puerto Rico.Perez-Gelabert, D.E. (2002). "Paulinia acuminata (Orthoptera: Pauliniidae) introduced to Puerto Rico, West Indies", Cocuyo' 12: 5. The giant gourami has long been known to prefer S. molesta and feed on it voraciously. It has been successfully used to control S. molesta in reservoirs of Sri Lanka.
  Mechanical control
  Plants are removed by machine or harvesting equipment and by hand; the latter is suitable only for small infestations. Harvesting equipment also can encounter difficulties, as it cannot remove all of the infestation, it cannot access shallow areas, and equipment can be inhibited by large masses of the plant. Once removed, the plant must be dried, burnt, or disposed of in a manner that ensures it will not re-enter the waterway. Other methods to control the aquatic weed are dredging and chaining.