Japanese beetle (Popillia japonica) adults are voracious feeders on a wide range of fruit plants, devouring foliage, blossoms and fruit.  The grub feeds on plant roots.

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Appearance:

  • The Japanese beetle adult is an insect that has a metallic green hard body with coppery brown wings.

  • The larva is a white, legless grub that inhabits the soil.

  • They feed on over 300 different plant species. Skeletonized leaves are a very distinct indicator of Japanese Beetles.

Damage:

  • Japanese beetle adults feed on leaves, blossoms, and fruit; leaves are skeletonized

  • Larvae feed on plant roots.

  • Larvae spend 11 months in the ground and Adults emerge from June-August

Timing:

  • The larvae (also called grubs) overwinter in the soil. The grubs feed on grass roots until the cold weather sets in and return to the surface in the springtime.

  • Japanese beetle adults emerge from the soil in mid-summer, and complete their life cycles by late summer.

Treatment:

  • First thing in the morning, when beetles are slow, have a bucket of soapy water beneath the foliage and knock the beetles into the bucket.

  • Neem oil application to disrupt feeding

  • Pheromone traps: These types of traps may attract more beetles than they actually catch if not used properly. We recommend the use of a mass trap. Visit our YouTube channel for detailed instructions to build a mass trap.

  • Kaolin clay can protect crops.

  • Milky spore, a bacteria, applied to the soil in Sept-Oct or April-May, acts as a grub control.

Sources: Patrick L. Byers, Horticulture Specialist and Michael Phillips, “The Holistic Orchard”