Field trial of relative efficacy of abate and Bacillus thuringiensis against Simulium himalayense larvae ( Diptera simulidae)

Simulium himalayense (Diptera simulidae) are known pests which cause severe biting nuisance in North-East region and breed in its fast flowing rivers and rivulets. A field trial was undertaken to control this nuisance with the help of larvicides and to help ascertain relative efficacy of Abate and B thuringiensis against Simulidae. Abate proved to be an effective larvicide for river treatment wherein 0.1 PPM resulted in 100% larval reduction while in small streams, the treatment with Teknar ( Bacillus thuringiensis) with 10 PPM for 10 minutes resulted in 80% larval reduction. The results of the present study showed that Abate was more effective in rivers while B thuringiensis proved to be useful in controlling the breeding in the rivulets. An integrated approach using chemical and biological agents is recommended and considered ecologically sound as it does not affect the fish and potability of water.