Study summary
Effects of Bacillus thuringiensis var. israelensis on target and nontarget organisms: a review
Boisvert M, Boisvert J
Read the original paper- Study type
- Review
- Year
- 2000
- Published in
- Biocontrol Science and Technology, 10(5):517-561
- Evidence strength
- Well-supported evidence
Summary
A comprehensive review of the published evidence on what Bti kills and what it does not, gathering studies on its effect on the target mosquito and black fly larvae as well as on non-target wildlife such as mammals, birds, fish, amphibians, and other aquatic insects. The purpose is to characterize how target-specific Bti really is, which is the central safety question for a larvicide meant to go into standing water.
Key findings
The review concludes that Bti is highly toxic to the larvae of mosquitoes and black flies but essentially non-toxic to mammals, birds, fish, amphibians, and the large majority of non-target invertebrates at the doses used for mosquito control. The clearest exceptions are a few closely related aquatic flies (such as some midges) that can be affected at higher concentrations, which is why operational dosing matters. Overall the evidence supports Bti as one of the most selective insecticidal tools available, killing the intended larvae while leaving most of the surrounding ecosystem, and household pets, unharmed.
Limitations
It is a review of many separate studies, so methods and doses differ across the underlying work. Non-target effects are dose-dependent, and effects on a few closely related aquatic insects at high concentrations are noted, so target-specific does not mean zero effect on every organism. The review addresses ecological and non-target safety, not a measured reduction in bites for any individual person.