Milky Spore is a naturally occurring microscopic bacteria (Bacillus popilliae) that kills Japanese beetle grubs before they can grow into ravenous adults. It's a long-term solution because it survives winter temperatures. The Milky Spore population increases each year, reaching peak effectiveness about three years after application, and lasts ten years or more. Safe for people, pets and beneficial soil organisms Use in tandem with our Grub Guard for protection during the first two years while this control reaches maximum effectiveness To make application easy, use the Milky Spore Applicator 10 oz. can covers 2,500 sq. ft. 40 oz. can covers 10,000 sq. ft.