The Extent of Salvinia Infestation in Kerala (S. India): Its Impact and Suggested Methods of Control

Abstract

The aquatic weed Salvinia molesta (syn. S. auriculata) has spread to many parts of the tropics and subtropics. In Kerala, it has become established as a dreadful weed occupying large areas of open water, causing navigational problems, interfering with irrigation and fishing, rendering the water unfit for human consumption, and facilitating mosquito breeding, etc. The H2S generated in the decaying weed-mass in the water is destructive of generative equipment in hydroelectric installations, blocks intake apertures of ships, and damages engines of small motor-boats. In addition, the weeds cause reduction in the stored water of reservoirs, owing to excessive evapotranspiration, while thick mats of Salvinia, which later form large floating islands supporting secondary and tertiary colonizers, may be instrumental in the gradual drying up of natural and man-made water-bodies. These are very serious matters which have to be tackled effectively.