Study summary
Bacillus thuringiensis serovariety israelensis and Bacillus sphaericus for mosquito control
Lacey LA
Read the original paper- Study type
- Review
- Year
- 2007
- Published in
- Journal of the American Mosquito Control Association, 23(2 Suppl):133-163
- Evidence strength
- Well-supported evidence
Summary
A review of the two bacterial larvicides most used against mosquitoes, focused on Bacillus thuringiensis subspecies israelensis (Bti). It covers how Bti works, how well it kills larvae in the field, how long it lasts in water, and its effect on other wildlife, drawing on decades of laboratory studies and operational mosquito-control programs. This is a review of source-control larvicides that kill larvae in water, not a study of personal repellents that stop bites on skin.
Key findings
Bti is a highly effective larvicide against mosquito and black fly larvae. The bacterium produces protein toxins that a larva must eat; the toxins then rupture the cells lining its gut, killing it before it can mature into a biting adult. The review reports that Bti is environmentally selective, meaning it kills the target larvae while sparing most other organisms, and that it breaks down quickly in the environment so it does not build up. Because larvae must ingest it and it settles or degrades over days, reapplication is needed to keep treating water that keeps producing mosquitoes. It is a mainstay of professional mosquito-control programs worldwide.
Limitations
As a narrative review rather than a single controlled trial, it synthesizes many studies of varying design. Real-world larval kill depends on getting the material to where larvae feed, on water conditions, and on retreatment timing, so field results vary. The endpoint is larval control and population reduction, not a measured drop in how often a specific person is bitten, and it concerns source control in water rather than protection on skin.