Healthy Ponds Mosquito Controls Bti microbial larvicide kills developing larvae in ponds, lakes, irrigation ditches, catch basins, fountains, and other standing waters before they become biting mosquitos that may transmit West Nile Virus, encephalitis, malaria, and other illnesses. Two-pound shaker jar dispenses granular product into standing. Apply every 7 to 14 days for effective control in small areas. Also available in 10- and 40-lb. bags, disposable dispensers that treat 300- and 2,500- gal. areas for 30 days, and premeasured packets for Healthy Ponds pond cleaner dispensing systems. Larvae death often occurs within 1 hr. at field use rates. Targets only mosquito and blackfly larvae and, when used as directed, has no adverse effects on people, plants, beneficial insects, and pond-dwelling fish, crustaceans, and amphibians. Not for use in treated drinking water reservoirs.