In 1916, the Japanese beetle (Popilia japonica) was found in New Jersey, USA, an attractive invasive species from its native Japan, sporting iridescent brown elytra (wing coverings) and green head and thorax. Although not a pest in Japan, populations of the scarab beetle rapidly expanded in North America where it was free from predators and parasites, and spread west across the continent. Both the adult and larval form of this insect is a pest. The beetles tend to feed as a group, and cause severe damage to plants as together they skeletonize leaves, and consume flowers and fruit of a very broad number of host plants. The white, C-shaped larvae hatch out of eggs laid in the soil and do damage especially to grasses and seedlings, as they feed steadily on root systems. By late summer they reach full-size, then go dormant underground for the winter. Grubs are especially damaging to turf grasses in golf courses, cemeteries, and other lawns. They emerge in early June as beetles. Food- and hormone- containing traps for beetles are commercially available, however, because they attract beetles so effectively they may in fact attract more beetles to an area than they can remove. Physically removing beetles helps rid this pest as they like to cluster. Japanese beetles are susceptible to several bio-control agents; bacteria causing milky spore disease (Paenibacillus popilliae) and an insect-attacking nematode (Heterorhabditis bacteriophora.) are effective and can be obtained for use against this beetle. There also are insecticides labeled for use against Japanese beetles.

(CABI 2011; Cranshaw 2007; Potter, Potter and Townsend 2006; Wikipedia 2011

Japanese beetles are native to east Asia; however, they were accidentally introduced into the United States in 1916 (Encyclopedia Britannica Online). In North America they occur from Georgia west to Missouri, north to Ontario and east to Nova Scotia, with some populations now in California (NC Co-op Extension Service).

Biogeographic Regions: nearctic (Introduced ); oriental (Native )

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Like all beetles, Japanese beetles have a hard exoskeleton and chewing mouthparts (Barnes, 1987). The adult beetle is 10-12 mm long with a metallic body (usually green or copper) and bronze wing covers (Fleming, 1972). These hardened wing covers are actually modified wings called elyptra (Meglitsch andSchram, 1991).

The Japanese beetle egg is white and almost translucent. It's shape is spherical and it is about 2 mm in diameter(www.ncsu.edu, 1).

The larvae are white grubs with a grayish cast to them because of the aggregation of soil and fecal material in their hindgut. They have a dark brown head and three pairs of legs. They are characterized by their "C"-shape form, grow to be about an inch long, and can be distinguished from other larvae by their "V"-shaped pattern of spines underneath their abdomen (Grupp, 1).

The pupa is usually 13 mm long and tan colored right up until the adult emerges, when it turns metallic green. Its appendages are pressed to the body, but otherwise it resembles the adult form(www.nscu.edu, 1).

Japanese beetles can apparently live anywhere there is sufficient foliage to feed on. They are not limited to forests or grasslands, but often live on farms, cities, and even your garden.

Terrestrial Biomes: savanna or grassland ; forest

Japanese beetles are known to feed on a variety of trees, shrubs, grasses, and nursery plants. The adults feed on the flowers, fruit, and leaves of the such plants as grapes, peach, rose, cherry, soybea, hibiscus, Indian mallow, dahlia, zinnia, horsechestnut, willow, elder, and sassafras(NC Coop Extension).

The larva feed on the roots of grass-like plants while they overwinter(Encyclopedia Britannica Online).

Japanese beetle have one complete life cycle that lasts an entire year. In mid-summer, the adult beetles emerge from the pupal stage. During warm days, the beetles fly and congregate on host plants to feed and, more importantly, mate. After mating, that afternoon the females deposit one to four eggs in loose, moist soil. In the female beetle's life, she will produce 40-60 eggs. Two weeks after the eggs were deposited, the larva emerge. They feed on the fine roots of grass-like plants and remain active until cold weather, when they "hibernate" under the soil surface. When the soil warms up again in the spring, the larva move closer to the surface and resume feeding. Soon after that, the grubs remain inactive for a 10-day period until pupation begins. The pupal stage lasts for 8 to 20 days, then the adults emerge (North Carolina Extension).

This species is not protected, and in North America measures are being taken to control the spread of this pest. Insecticides kill adult beetles, but do not prevent reinfestation. Some of the beetle's natural predators such as wasps and flies have been imported from Japan to help control the population. Moles, shrews, skunks, and birds also significantly decrease the population by eating the larva form. Biological control is available using a bacterium, Bacillus popilliae, which causes milky disease in the larvae--thereby greatly reducing Japanese beetle populations (Encyclopedia Britannica Online, NCCES, Grupp).

US Federal List: no special status

CITES: no special status

Rounded Global Status Rank: GNR - Not Yet Ranked

Canada

Rounded National Status Rank: NNR - Unranked

United States

Rounded National Status Rank: NNR - Unranked

Japanese beetles are pests of agriculture and horticulture. especially in North America.