Bacillus popillae, or milky spore, is a naturally occurring bacterium which is used by gardeners to eradicate Japanese beetles. It was introduced under the US program designed to control these pests in the latter half of the 20th century (when pathogens began to be used worldwide as an organic means to treat various pests and diseases). Japanese beetles infestations can cause significant damage to crops, since they feed on more than 400 plants and herbs. When applied in a certain way milky spores make larvae get infected and die. The bacterium is proven to be highly effective, and its effect lasts for years. So, this all organic treatment method will not only bring you peace of mind but will also help to save some finance.

How It Works

Milky spore is ingested by Japanese beetles with their natural food. Then the spores germinate inside the grubs causing a milky spores disease which makes them die. When a grub perishes, millions of new spores are released into the ground killing more pests. Within a period from one to three years the spores disease will effectively control the beetles in the local area. Milky spores come in two forms:

  • powder;
  • granules.

Using powder and drop spreader is the most common way to distribute Bacillus popillae over your lawn. The bacterium is also available in the form of granules which are distributed with the help of broadcast spreader.

It is important to note that milky spore is harmful for Japanese beetles only. It is completely safe for other insects, birds, pets, animals and humans. It doesn’t influence the crops, it is not a chemical insecticide.

Milky Spore for Japanese Beetles Control

When and How to Use

The bacterium can be distributed in any form any time of the year except when the ground is frozen. The most beneficial season is fall, since the grubs move closer to the surface to the warmer soil to feed on plants roots. It is recommended to apply one teaspoonful of the powder on your lawn every four feet. To be sure you distribute the spores in a right way, follow the directions given on the package. To buy enough bacteria to treat the whole garden plan on about one pound for every 4,000 square feet of lawn.

The keystone of bacterium distributing is enough watering. Milky spores are negatively affected by the sun, hence the lawn must be immediately watered after the distribution. When the spores penetrate into the soil they remain there until hungry grubs swallow them. Because of the disease the larvae will die releasing more additional spores and continuing the cycle of grub eradication.

In order to fasten the process after treating Japanese beetle grubs, switch to adult individuals (you may simply handpick them regularly). In case you live in areas which are vulnerable to Japanese beetles infestations, encourage your neighbours to join your eradication plan to achieve the best results.