Milky Spore Treatment for Grubs

Japanese Beetle grubs--the larvae that develop into the adult beetle--can invade your lawn, eating grass and destroying its root system. That's just a precursor to the damage to about 275 species of trees, shrubs and flowers they do when they are adult beetles. Here's a quick rundown of one way to deal with these annual pests with milky spore treatment.

Milky Spore Disease

Milky spore disease, also known as the bacterium Bacillus popilliae, attacks and kills only the Japanese Beetle grub. The grubs eat the spores, which then multiply inside the grub. After about two weeks, the grub dies. When it decomposes, millions of more spores are released into the soil.

Effects

Milky spores can take about a year to show any effectiveness, with complete control affected after two or three years in warm climates. The bacterium work for about 15 to 20 years after that.

When to Treat

Milky spores should be spread on your lawn in warm weather only, when the temperature is at least 55 degrees.

How to Treat

Spread the spores in even, crisscrossing rows, forming a grid. After they have been dispersed, water them in for about a 30 minutes.

Safety

Milky spores are not pesticides, so they will not harm bodies of water. They are safe if exposed to children or pets.