What is Bti and how is it used in vector control?

• A. Bti is a chemical insecticide used on adults.
• B. Bacillus thuringiensis israelensis; used as a larvicide in streams.
• C. Bti is a disinfectant for surfaces.
• D. Bti is a fertilizer.

Answer: (B)

Bti stands for Bacillus thuringiensis israelensis, a bacterium used as a biological larvicide in water. In streams and other aquatic habitats, Bti works by producing toxins that must be ingested by mosquito and black fly larvae. Once the larvae consume the toxins, their gut cells are damaged and they die before they reach the adult stage, so fewer biting adults emerge. This makes it a targeted tool for vector control, focusing on the larval stage and reducing environmental impact when used as directed. It is not a chemical insecticide for adults, nor a surface disinfectant or a fertilizer.