Aquatic weed classification, environmental effects and the management technologies for its effective control in Kerala, India

Abstract: Aquatic weeds, the unabated plants completing life cycle in water, are a serious menace to the environment. Dense colonies of aquatic weeds are observed in the southern regions of Kerala which mainly includes Ernakulam, Kottayam, Idukki and Alappuzha districts. The noxious aquatic weeds invade inland water masses, estuaries inshore regions of seas and are now abandoned. The rapid and excessive growth of aquatic weeds in varied and wide environmental condition limits the sustained performance of many drainage and irrigation system, reducing the productivity of agricultural land. Aquatic weeds are classified into emergent, floating and submerged weeds according to the various habitats. Many species are found in Kerala which were originally introduced into botanical gardens. The major aquatic weeds found in Kerala include Salvinia spp., Eichhornia crassipes, Pistia stratiotes, Alternanthera spp., Azolla, common duckweed, and Hydrilla verticillata. Reduction or elimination of aquatic weeds is possible through well planned management strategies which includes preventive and control (biological, physical, chemical, eco-physiological) measures. A successful weed control program depends on the resources available, the weeds present and the ability to carry out effective control methods. Operational research and /or pilot projects have to be initiated in the problematic areas on long term basis, using technical recommendations derived from research experiments.