U.S. gardeners and homeowners have been waging a battle against Japanese beetles and their grubs for some time. While the beetles fly from garden to garden without boundaries, chewing on prized foliage and flowers, it is the beetle grubs that live underground that are of bigger concern. Japanese beetle grubs can ruin a lawn by chewing away at grass root systems, and then attack your garden after turning into damaging adults. One of the most effective and long-lasting ways to get rid of these grubs is to use milky spore.
What is Milky Spore?
According to the University of Delaware Cooperative Extension, milky spore spreads through soil when it is ingested by Japanese beetle grubs, killing them. When a grub dies, millions of additional spores are released into the soil, spreading, and killing more grubs. Over the course of one to three years, milky spore disease will effectively control a local population of Japanese beetle grubs. The spores will continue to spread to a wider area and be effective for many years. There are two ways to distribute milky spore.
Milky Spore Powder
The most common method for distribution of milky spore is to use milky spore powder and a drop spreader. Milky spore powder is very fine, and cannot be spread with a broadcast spreader. A drop spreader places milky spore on the lawn in spots where it will be watered into the soil and moved through it by Japanese beetle grubs. When using this method of spreading milky spore, Hetzler Farm and Feed suggests that you apply a teaspoon of milky spore every four feet, in rows spaced four feet apart. Application should take place three times per year for two years.
Milky Spore Granules
Milky spore can also be distributed over your lawn in granule form. This involves using a broadcast spreader. In this case, the milky spore has been embedded into small granules. If you like, you can spread your milky spore granules on your lawn along with granulated fertilizer. Read package directions to determine the proper settings for spreading an effective application of milky spore.
Water is Key
The final key to distributing milky spore in your lawn is water. Milky spore is negatively affected by sunlight, and is best spread on an overcast day, then watered in thoroughly and immediately. Once the spores have moved into the soil, they will lie in wait for hungry grubs to ingest them. The grubs will die, releasing more spores and continuing the cycle of grub reduction.
One final note: a group effort will make milky spore even more effective. Encouraging your neighbors to apply milky spore to their lawns will benefit your entire community.