If you've had a rough year battling Japanese beetles, now is the time to control them. Many gardeners are familiar with Japanese beetle adults that cause damage to many flowers, vegetables and fruits.
While there are chemical controls for these and other ground dwelling beetles, there are effective ecologically friendly controls as well. Remember only one percent of the insects in your yard are ones that will cause significant damage to your plants.
One of the best controls attacks the Japanese beetle not when it's an adult, but at the c-shaped, cream colored grub or larval stage in the soil. It's at this stage that it's most vulnerable. If you can kill the grubs, you'll have fewer adults next year. There are a few products that are safe for the environment and effective.
Beneficial nematodes are microscopic, worm-like creatures that parasitize or prey on the grubs. Spray the nematodes now on the lawn and soil areas where the adults were feeding this summer. That's where most of the larvae are located. Water the area well and keep the soil moist for a number of days so the nematodes can travel to prey on the grubs. The nematodes don't overwinter so need to be sprayed annually in early or late summer.
The other product in milky spore powder. This is a bacteria that has been used since the 1940s to control Japanese beetle grubs and it only attacks this type of grub. This powder or granule works best in areas with high concentrations of grubs, such as 10 to 12 grubs per square foot. With fewer grubs, it is not as effective.
