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The Japanese beetle, an extremely destructive pest, is native to Japan and was first discovered in the United States in 1916. Since the larvae (white grubs) feed on the roots of numerous plants and grasses while beneath the soil and the adults consume leaf matter above ground, the Japanese beetle causes monumental damage to golf courses, gardens, fruit trees, shrubs, lawns and nurseries. Japanese beetles can fly as far as five miles in search of food and mating partners.

Characteristics

  • Japanese beetles don’t fly very well
  • Adult Japanese beetles are approximately 1/2 to 3/4 inch long
  • Japanese beetles eat around 300 species of plants, even poison ivy
  • Japanese beetles are present in most Eastern and Midwestern states
  • If available, they will also feed on the fruit growing on the plants and flowers
  • The adult Japanese beetles excrete pheromones to attract other beetles and overwhelm plants
  • Adult Japanese beetles feed on the leafy material between the veins of leaves, thus damaging plants
  • The adults have metallic blue-green heads, coppery wing casings and small white hairs lining each side of the abdomen

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Reproduction

  • Japanese beetles go through four stages of development, egg, larva, pupa and adult
  • An adult female may lay as many as 40 to 60 eggs in her lifetime
  • Eggs are laid individually in the fall, or in small clusters near the soil surface, amid the roots of grasses
  • The eggs hatch within approximately two weeks
  • Japanese beetle larvae (white grub) hibernate over the winter in the soil
  • The larvae of Japanese beetles emerge in the spring when soil temperatures rise again
  • Within 4-6 weeks of breaking hibernation, the larvae will pupate and then emerge as adults
  • It takes one full year for an egg to mature into an adult beetle
  • Most of the beetles’ life is spent as a larva, with only 30-45 days spent as an adult
  • The life-cycle of the Japanese beetle is about two years

Prevention

  • Apply sprays in the morning
  • Natural repellents include garlic, catnip, tansy and chives
  • Shake plants to knock off the Japanese beetles onto the ground and destroy them
  • Japanese beetles may be manually controlled using a soap-water spray mixture
  • Strategically place pheromone traps around the perimeter of your property during May through July
  • Walking several times over infested plots of lawn where the larvae reside will kill the grubs just beneath the soil, according to researchers