BVA-2 is a highly refined petroleum-based product that is used only on the pupal stage of the mosquito. This is a last resort material that is used to prevent adult emergence. It works by changing the surface tension of the water surface, causing both the larval and pupal stages to drown.
Because of its potential to affect other air-breathing aquatic insects, this insecticide is the least preferred mosquito control method used by the District. This insecticide does break down quickly in the environment, persisting as an effective surface film for only a few hours at best. Complete breakdown of this insecticide occurs within a few days. This chemical control strategy can be quite costly both in time and materials.