Chennai corporation begins using eco-friendly larvicide to kill mosquitoes

CHENNAI: Adopting an environment-friendly way to target mosquito larvae, the city corporation has begun using a specific strain of Bacillus thuringiensis (Bti), a bacterial larvicide.
Unlike mosquito larvicidal oil (MLO), used earlier, that cuts air supply to water due to the oil layer, Bti produces protein molecules that when eaten by larvae bind to their gut walls, cause changes leading to their death.Other species in the water bodies would remain intact while the larvae die.
“MLO is made of chemicals and being oil, it creates a thin film of oil thus obstructing the respiratory process of larva and killing them. But it affects other species too,” said an official. Senior officials said this was one of the civic body’s many plans to adopt environmentally friendly methods of eliminating larvae.
Bti affects only mosquitoes and other Nematocera. It can be sprayed on large areas after being mixed with water or directly mixed in containers holding water.
The civic body had been procuring a litre of MLO at Rs 80 against VectoBac that is being procured by the civic body at Rs 1,300 per litre. “10ml of bacterial larvicide is enough for 1 litre of water to be used and thus the quantity needed is less as compared to oil despite the huge cost,” an official said.