Bti (Bacillus thuringiensis israelensis) is currently the most widely used bioinsecticides in the world for mosquito control. In 2006, an experimental mosquito control programme was run in part of the Camargue with scientific monitoring of the non-target wildlife, under the auspices of the Camargue Regional Natural Park.
A 4-year study carried out by the Tour du Valat has revealed that Bti has a significant effect on the diet and feeding rate of house martins, which results in significantly lower breeding success at the sites sprayed as compared with the control sites. It is the first study in the world demonstrating a negative effect of Bti on vertebrate populations following the selective eradication of some prey and reporting on its downstream effects. Given the role played by Nematocera (sub-group of Diptera including mosquitoes and chironomids, which are extremely sensitive to Bti) in the food web of aquatic ecosystems, the use of Bti is likely to affect many animal species.
Bti mosquito control operations should thus be accompanied by awareness raising campains and be implemented within an action plan integrating hydrological management of mosquito-producing habitats, the dispersal probability of mosquitoes, the social demand to decrease their nuisance, as well as the protection of sensitive habitats with a high natural heritage value.
These findings were published in the Journal of Applied Ecology, and were also reported on in the ” magazine Nature online [1]“.
Contact Brigitte POULIN: [email protected] [2]