Milky Spore Powder is a 1-time application using 1 teaspoonful every 4 feet in a checker board pattern on lawn. Natural bacteria controls grub state of Japanese beetles. Remains dormant in soil until grubs begin feeding on grass roots to ingest it. Spore begins to multiply after ingested, killing grub from within. Will not harm humans, pets, shrubs, beneficial insects, or the environment. Safe for use around wells, ponds, and streams. 10 year performance guarantee, can last up to 20 years. Apply any time ground is not frozen. OMRI (Organic Materials Review Institute).