Milky Spore in Compost: Why It Won't Persist or Spread

Milky spore bacteria (Bacillus popilliae) controls Japanese beetle grubs slowly in lawns. In compost heaps, it won't persist—it requires living grub hosts to multiply. Without abundant grubs, heat and decomposition destroy the bacteria before it becomes useful. Don't waste milky spore on compost; apply directly to turf where grubs feed.