Bioinsecticides: does biological mean safe?

How to determine if an insecticide is environmentally safe? This is the question addressed by the Canadian TV (RadioCanada) as part of the show “The Green Week” in a documentary in which Guillaume Tetreau has been interviewed for its expertise on this topic. This documentary (in French), entitled « Le Bti, un larvicide inoffensif ? » and broadcasted saturday 18th April 2020, is available in replay on RadioCanada website (

Bti is a bioinsecticide – which means that it is produced by a living organism, the bacterium Bacillus thuringiensis subsp. israelensis. In the light of its apparent safety for non-target organisms, Bti has progressively replaced chemical insecticides that were historically used for mosquito control. In Europe, it has become in a decade the only insecticide authorized for mosquito control at the larval stage. In the context of the worldwide biodiversity crisis, the hegemony of Bti is worrying and a growing number of study question its status of a “safe” insecticide. This documentary aims at compiling the current knowledge on Bti impact on the environment and the ecosystems, notably enlightening available alternatives implemented in some countries.

This reportage echoes a review article recently published in the journal Science of the Total Environment, dealing with the environmental and socioeconomic aspects of mosquito control using Bti:

Environmental and socioeconomic effects of mosquito control in Europe using the biocide Bacillus thuringiensis subsp. israelensis (Bti). Brühl CA, Després L, Frör O, Patil CD, Poulin B, Tetreau G, Allgeier S. Sci Total Environ. 2020 Mar 21:137800. doi: 10.1016/j.scitotenv.2020.137800