Mosquito Dunks when wet, release a biological larvicide that is eaten by the baby mosquitoes (larvae). Mosquito larvae that eat the larvicide are dead within 24 hours. These products are effective even after repeated wetting and drying.
Aquabarrel™ suggests that the Mosquito Dunks be used in rain barrels, cisterns andother places where there is stagnat water source.
Bti ‘s active ingredient is a microorganism that mosquito and blackfly larvae eat. (Bti is short for Bacillus thuringiensis subspecies israelensis.)
Bti produces toxins that are effective at killing several species of mosquitoes and blackflies, while having almost no effect on other organisms.
Bti is essentially nontoxic to people, pets and wildlife. Unlike typical nerve-poison insecticides, Bti acts by producing proteins -toxic crystal- that reacts with the cells of the gut lining of larvae. The proteins paralyze the digestive system, and the mosquito or blackfly larvae stops feeding within hours.
The 6 pack donuts float and are used in ponds, pools of standing water and birdbaths. Expect them to dissolve over the course of about one month. Do your part to reduce the spread of West Nile Virus and Equine encephalitis – use Bti Mosquito Dunks from Aquabarrel.com
For more details from the EPA