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
- CABI, 2011. Popillia japonica (Japanese beetle) [original text by M. Klein]. In: Invasive Species Compendium. Wallingford, UK: CAB International. http://www.cabi.org/isc/?compid=5&dsid=43599&loadmodule=datasheet&page=481&site=144
- Cranshaw, W. 2007. Japanese beetle. Colorado State University Extension. Retrieved December 6, 2011 from http://www.ext.colostate.edu/pubs/insect/05601.html
- Potter, M.F., D.A. Potter and L.H. Townsend, 2006. Japanese beetles in the urban landscape. University of Kentucky, College of Agriculture. Retrieved December 6, 2011 from http://www.ca.uky.edu/entomology/entfacts/ef451.asp
- Wikipedia, The Free Encyclopedia. 4 December, 2011. “Japanese beetle”. Retrieved December 6, 2011 from http://en.wikipedia.org/w/index.php?title=Japanese_beetle&oldid=464090637
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 )
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
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).
Flowering Plants Visited by Popillia japonica in Illinois
(this observation is from Hilty; this beetle gnaws [gnw] on the flowers of the host plant below)
Fabaceae: Amorpha canescens gnw np (H)
Life History and Behavior
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).
Molecular Biology and Genetics
Statistics of barcoding coverage: Popillia japonica
Public Records: 0
Specimens with Barcodes: 9
Species With Barcodes: 1
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
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
Japanese beetles are pests of agriculture and horticulture. especially in North America.
The beetle species Popillia japonica is commonly known as the Japanese beetle. It is about 15 millimetres (0.6 in) long and 10 millimetres (0.4 in) wide, with iridescent copper-colored elytra and green thorax and head. It is not very destructive in Japan, where it is controlled by natural predators, but in America it is a serious pest of about 200 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees and others.
It is a clumsy flier, dropping several centimeters when it hits a wall. Japanese beetle traps therefore consist of a pair of crossed walls with a bag or plastic container underneath, and are baited with floral scent, pheromone, or both. However, studies conducted at the University of Kentucky and Eastern Illinois University suggest beetles attracted to traps frequently do not end up in the traps, but alight on plants in the vicinity, thus causing more damage along the flight path of the beetles and near the trap than may have occurred if the trap were not present. 
These insects damage plants by skeletonizing the foliage, that is, consuming only the leaf material between the veins, and may also feed on fruit on the plants if present.
As the name suggests, the Japanese beetle is native to Japan. The insect was first found in the United States in 1916 in a nursery near Riverton, New Jersey. It is thought the beetle larvae entered the United States in a shipment of iris bulbs prior to 1912, when inspections of commodities entering the country began. "The first Japanese beetle found in Canada was in a tourist's car at Yarmouth, arriving in Nova Scotia by ferry from Maine in 1939. During the same year, three additional adults were captured at Yarmouth and three at Lacolle in southern Quebec."
Life cycle 
The life cycle of the Japanese beetle is typically one year in most parts of the United States, but this can be extended in cooler climates; for instance, in its native Japan, the beetle's life cycle is two years long as a result of the higher latitudes of the grasslands required for the larval stage. During the larval stage, the white grubs can be identified by their V-shaped raster pattern.
During the larval stage, the Japanese beetle lives in lawns and other grasslands, where it eats the roots of grasses. During that stage, it is susceptible to a fatal disease called milky spore disease, caused by a bacterium called milky spore, Paenibacillus (formerly Bacillus) popilliae. The USDA developed this biological control and it is commercially available in powder form for application to lawn areas. Standard applications (low density across a broad area) take from one to five years to establish maximal protection against larval survival (depending on climate), expanding through the soil through repeated rounds of infection.
Research performed by many US extension service branches has shown pheromone traps attract more beetles than they catch. Traps are most effective when spread out over an entire community, and downwind and at the borders (i.e., as far away as possible, particularly upwind), of managed property containing plants being protected. Natural repellents include catnip, chives, garlic, and tansy, as well as the remains of dead beetles, but these methods have limited effectiveness. Additionally, when present in small numbers, the beetles may be manually controlled using a soap-water spray mixture, shaking a plant in the morning hours and disposing of the fallen beetles, or simply picking them off attractions such as rose flowers, since the presence of beetles attracts more beetles to that plant.
Host plants 
Japanese beetles feed on a large range of hosts, including leaves of plants of the following common crops: Beans, strawberries, tomatoes, peppers, grapes, hops, roses, cherries, plums, pears, peaches, raspberries, blackberries, corn, peas, birch trees, linden trees, blueberries, and these genera:
- Ipomoea (morning glory)
- Malus (apple, crabapple)
- Ocimum (basil)
- Ribes (gooseberry, currants, etc.)
- Rubus (raspberry, blackberry, etc.)
- Salix (willows)
- Thuja (arborvitae)
|Wikispecies has information related to: Japanese beetle|
|Wikimedia Commons has media related to: Japanese beetle|
- "Managing Japanese Beetles". University of Kentucky.
- "Behavioral Explanations Underlying the Lack of Trap Effectiveness for Small-Scale Management of Japanese Beetles.". Journal of Economic Entomology.
- Japanese Beetle, Canadian Food Inspection Agency
- Japanese Beetle control strategies
- pests - selfsufficientish - pests.
- Japanese Beetle, Canadian Food Inspection Agency
EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.
To request an improvement, please leave a comment on the page. Thank you!