Impact of release of Neochetina spp. on growth and density of water hyacinth Eichhornia crassipes
Water hyacinth (<em>Eichhornia crassipes</em>) is an invasive aquatic macrophyte which creates several problems in irrigation system of rivers. To control their rapid distribution in water bodies the biological control method was carried by employing weevils <em>Neochetina bruchi</em> and <em>Neochetina eichhorniae</em> on river based field trial. The study demonstrates effectiveness of biocontrol weevil open field release on experimental site (Chittar river). When compared to first release in field, the weevil intensity was increased in numbers. Active scraping was observed in the leaves and decay spots were seen in the stems of weed. Both <em>N. bruchi</em> and <em>N. eichhorniae</em> (250 No) were introduced biyearly at experimental site for one year. During these two years of observation period, stunted growth and reduced population were observed in the study site. The study highlights importance of <em>Neochetina</em> spp. on the management of <em>E. crassipes.</em>