It’s a bacteria (Bacillus popilliae) that dwells in the soil, which has been identified as a disease that specifically attacks grubs from the Japanese beetle. Products that contain the spores are approved by the U.S. Environmental Protection Agency and they are sold specifically to help rid lawns of grubs.
Artificial chemical agents that wipe out grub populations can be harmful to pets, birds, and the water table. Naturally, there has long been a search for natural substances that would destroy grubs without doing other harm. Some people are convinced that milky spore is the answer. Sadly, that isn’t actually the case. Why?
First, the milky spore disease is mostly effective against the Japanese beetle grub. Not all grubs are from Japanese beetles. Second, the disease must first be ingested in grubs. When they die, millions of other milky spores are released. That means it can take several generations – perhaps a few seasons – for the spores to build up enough to be effective. Finally, When first introduced, milky spore decreased Japanese beetle populations by 41.5 percent, but since then the beetles have grown resistant with only 0.2 percent effectiveness, according to a Cornell University report.
Most homeowners conclude that their best options are the popular chemicals and the lawn care services, which also use chemicals. If milky spore fails, lawn owners might consider neem oil – a substance that acts to repel Japanese Beetles and their grubs.
There remain four choices; chemicals, milky spore, neem oil, or ignore the grubs.
What’s your preference?