Japanese beetle

Insect

Japanese beetle

Popillia japonica Newman

Coleoptera: Scarabaeidae

Distribution: Southeastern Canada and in most fruit-growing states in eastern US.


Japanese beetles can be present from June through September. Japanese beetle adults are metallic green or greenish bronze with reddish wing covers and several white spots near the abdomen tip and along the sides. Larvae are larger C-shaped grubs that live in the soil.

  • Crops Affected: Grapes

    Damage

    Japanese beetles feed on the upper leaf surfaces, leaving a lacelike skeleton. Injured leaves may turn brown and die if feeding is severe, but clusters are not attacked. Juice grape vines are resistant and tolerate some damage, but vinifera and hybrids are more susceptible. This pest can be a problem particularly in new vineyards using grow tubes. Frequent monitoring is required to reduce the risk of severe damage. Japanese beetle traps may attract beetles to vineyards, so their use is discouraged. Beetles lay eggs underground in grassy areas near vineyards, preferring soil with moisture. The white, C-shaped larvae (grubs) feed on grass and weed roots and overwinter underground in these areas.

    Management

    Cultural and biological controls of grubs may reduce subsequent abundance of adults.

  • Crops Affected: Apples, Cherries, Peaches, Pears, Plums

    Damage

    Attacks all tree fruits, particularly peach and apple. Adults (only) feed on the surface of the fruit and leaves of deciduous fruits (B, C). The fruit may be partly peeled and gouged in irregular shallow patches, or nearly devoured. The leaves are skeletonized (B). Damage is more severe in sandy locations, often occurring especially at orchard edges in proximity to grassy areas.

    Management

    Feeding damage from adults is sporadic and transient during the summer. If needed, an insecticide can be applied when leaf damage or the insects feeding on foliage are noted in the trees; retreatment may be necessary as new adults arrive. Biological control of Japanese beetle may be elected through use of milky spores of bacteria or nematode products.

    Similar Species

    Rose chafer [Macrodactylus subspinosus (F.)] adults are slender, long-legged beetles, fawn-colored with a reddish-brown head and thorax, and undersurface of the body black. Its larvae are also large, C-shaped grubs. Both rose chafer and Japanese beetle are relatives of green June beetle (Cotinus nitida), with whom Japanese beetle sometimes occurs in the adult stage. The two species can be distinguished by the differences in their size and coloration; also, unlike green June beetle, which can injure both green and ripening fruit, Japanese beetle prefers fruit that is close to ripe.

More Information on Similar Species

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