Mosquito dunks kill larvae. It's used as a mosquito population control in warmer areas. Me and a few neighbors used it this year with good results.
Get a 5 gallon bucket, add water/grass/leaves/dunk and let it sit for a few weeks. Every few weeks add more dunks. Put a stick in there so small animals don't get stuck when trying to get a drink.
Get a 5 gallon bucket, add water/grass/leaves/dunk and let it sit for a few weeks. Every few weeks add more dunks. Put a stick in there so small animals don't get stuck when trying to get a drink.