Two bacteria are commonly used as biological controls for mosquitoes: Bacillus thuringiensis (Bt) and Bacillus sphaericus serotype H5a5b, strain 2362 (Bsp). The Bt used around ponds is the subspecies Bacillus thuringiensis israelensis (Bti). Bti was registered with the EPA in 1983 for control of black flies, mosquitoes and midges and Bsp was registered for mosquitoes in 1991. Bti is sold as Aquabac®, VectoBac®, Mosquito Dunks® and Teknar®. Bsp is the active ingredient in Spheratax SPH (50G) and VectoLex®. Some products are powdered, some are liquid, and some are pellets. Users should check the labels to make sure the product chosen is labeled for use in their water body type.
Shoreline Knowledge Base
Wisconsin Department of Natural Resources individual chemical fact sheets:
Note: Products may not be registered for use in your state or locale. Check to be sure a specific use pattern is approved in your area before use. Check product labeling or your local state agency for more information. Most current product labels are available by visiting the product manufacturers website or at https://www.cdms.net
AquaBac 200G Granular Bacillus thuringiensis var. israelensis (Bti). Bti is eaten by the mosquito larva and becomes highly toxic to the larva killing them within minutes after ingestion. Since the bacteria are harmless to other mosquito and black fly larva predators, these predators continue to feed on the larva and work in concert with Bti to keep the larva population in check.
VectoBac 12AS (also known as SC; Suspension Concentrate) is an aqueous suspension formulation of Bacillus thuringiensis subsp. israelensis (strain AM65-52) for control of mosquitoes, black flies, and closely related fly larvae.
VectoMax FG is an advanced biological mosquito larvicide that combines the time-proven and environmentally compatible bacterial active ingredients Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus 2362 into a single microparticle.