This strain of Bacillus thuringiensis (Bt/H-14) provides very effective fungus gnat control for houseplant growers and home greenhouses. Populations of fungus gnats (often called "fruit flies") usually peak during winter and spring. The tiny adult insects lay their eggs in peat moss, humus-rich organic soil and potting media. The larvae then feed on plant roots, including those of young seedlings. With Knock-Out Gnats, the larvae ingest the larvicide and die! The water-dispersible granules are convenient to use! Mixing: Light infestation - 1/4 to 1/2 tsp per gallon Heavy infestation: 1 to 1 1/2 tsp per gallon. 4 oz. is approximately 48 tsp. Using the 1/2 tsp rate, it will make 96 gallons. Using the 1 tsp rate will make 48 gallons.