Aquatic vegetation and their natural hospitability to the immatures of Mansonia mosquitos, the vectors of Brugia malayi in Shertallai, Kerala, India.

Prevalence of various aquatic vegetation and their role in supporting vector breeding were studied by drawing plant samples from natural fresh water habitats in Shertallai region which is endemic for Brugia malayi. As many as 30 aquatic plant species were identified in addition to the most abundant and preferred host plants such as Pistia stratiotes, Salvinia molesta and Eichhornia crassipes which are of major concern due to their contribution for vector proliferation. Fallow lands and paddy fields recorded relatively a higher number of plant species. Natural breeding of Mansonia, the vector mosquitos was observed in 16 of them. Using the data on the prevalence, proportion of samples positive for Mansonia breeding and immature density, two indices viz, natural hospitability Index (NH) and Mansonia host plant Index (MHI) were developed for each plant species. Ranking of these plants in relation to Mansonia breeding was done based on these indices. Monochoria vaginalis has been identified to be one of the most important auxiliary host plant. Three grasses viz, Hygrorhiza aristata, Sacciolepis interrupta and Leersia hexandra were found to support all the three species of Mansonia viz, Ma. annulifera, Ma. uniformis and Ma. indiana with considerable immature density. The inclusion of these plants for weed/vector control is emphasized.