Yes, the bacteria target mosquito larve.

Though:

- It won't stop breeding in other standing water

- Depending on where you live, it could decimate the food source of other animals

- It attacks all mosquito's not just blood suckers

- I understand that there are conflicting reports on its effects on amphibians. I'm not sure how reliable the negative reviews are, or if it is "big citronella" sourced scare, but you may want to be cautious of which water sources you use them in.