Japanese Beetle: Most Wanted Pests Threatening Your Lawn [Part 3]

Japanese beetles were first found in United States in 1916, after being accidentally introduced into New Jersey. Thanks, New Jersey.

In Japan, the beetle has natural predators which keep it in check, but in the United States it is a major pest. The Japanese beetle feeds on more than 300 species of turf and ornamental plants, and its grub form feeds on the roots of grass, destroying your lawn in the process.

Japanese Beetle (Popillia Japonica)

The Japanese beetle is about ⅜” long as an adult, with a dark metallic green head and metallic dark tan wings. The defining characteristic is two white tufts at the rear and five white tufts on each side.

Japanese beetle larvae or grubs are “C” shaped and live in the soil and feed on grass roots – they’ve also been noted to feed on the roots of corn, beans, tomatoes and strawberries.

Japanese beetle grubs can be identified by the pattern of hairs on their hind end. Using a magnifying lens, you can see that the hairs on their hind end form a small “V” shape just below the anus.

Adults emerge from the soil in early July to feed, mate, and lay eggs. Individual beetles live about 60 days. Over 2 months females can lay a total of 60 eggs, which hatch and are about 1” long by September, feeding on your lawn’s roots the entire time. The grubs burrow underground in the fall, and survive the winter between 2-10” below the surface. They feed on your lawn again in May before become adults in July.

Prevention And Mitigation

Once you’ve identified that you have the Japanese beetle, there are some steps you can take to fight them and prevent them in the future.

  • Pick them off. Japanese beetles are slower in the morning, so you can pick them off with your hands and toss them in a bucket of soapy water.
  • Use a biological control created by the USDA called milky spore. This bacteria kills the grubs in your soil, and properly used is established over 1-5 years and effective for about 10 years. Contact Valley Green to make sure it is applied properly.
  • Be careful with your mowing. Mowing more than ⅓ of the blade off at one time, mowing too infrequently or mowing your grass shorter than 3-3-½” can add unnecessary stress to your lawn, making it more susceptible to damage from insects.
  • Follow healthy lawn practices. Contact Valley Green to set up regular lawn maintenance and we can monitor your lawn’s health. A healthy lawn is much less susceptible to insect damage.
  • Lastly, you can use control products to reduce and remove the population. The best time to use control products is in the spring, before mid-June. Call Valley Green Companies to safely apply control products on your lawn.

Remember, if you need help we’re right down the road. Give us a call today!