Effective and eco-friendly delivery of a Bacillus thuringiensis-based insecticide in Aedes albopictus larvae

Climate change and trade globalisation is causing the expansion of mosquitoes areals to non-endemic regions, together with the pathogens transmitted by their bite. To control this spread, we focused on the production of an innovative biorational floating raft containing a bioinsecticide and an attractant (i.e., Bacillus thuringiensis var. israelensis, Bti, and the yeast Saccharomyces cerevisiae) to control mosquito larvae. We performed bioassays with a Bti-based commercial bioinsecticide to measure susceptibility to this product in larvae of different colonies of the Asian tiger mosquito (Aedes albopictus). Then, we tested the toxicity of chitosan-based hydrogel rafts containing the bioinsecticide alone or with yeasts in laboratory and semi-field conditions. The “MosChito” rafts resulted attractive for the larvae that eroded and ingested the hydrogel, and proved to be very effective in killing larvae over a month period demonstrating that the hydrogel preserved the bioinsecticide activity. Our results showed that “MosChito” rafts may represent an original, eco-based and user-friendly floating solution for mosquito larval control in residential or urban environments.