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
Japanese beetles are pests of agriculture and horticulture. especially in North America.
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 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 )
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
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).
Other Physical Features: ectothermic ; bilateral symmetry
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).
The Japanese beetle (Popillia japonica) is a species of scarab beetle. The adult measures 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, has iridescent copper-colored elytra, and a green thorax and head. It is not very destructive in Japan (where it is controlled by natural predators), but in North America and some regions of Europe, it is a noted pest to roughly 300 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees, and others.[1]
The adult beetles damage plants by skeletonizing the foliage (i.e., consuming only the material between a leaf's veins) as well as, at times, feeding on a plant's fruit. The subterranean larvae feed on the roots of grasses.
English entomologist Edward Newman described the Japanese beetle in 1841.
Adult P. japonica measure 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, with iridescent copper-colored elytra and green thorax and head. A row of white tufts (spots) of hair project from under the wing covers on each side of the body.[2] Males are slightly smaller than females. Grubs are white and lie in curled positions. A mature grub is roughly 1 inch (2.5 cm) long.[3]
Popillia japonica is native to Japan, but is an invasive species in North America and Europe.
The first written evidence of the insect appearing within the United States was in 1916 in a nursery near Riverton, New Jersey.[4] The beetle larvae are thought to have entered the United States in a shipment of iris bulbs prior to 1912, when inspections of commodities entering the country began. As of 2015, just nine western states of the United States were considered free of Japanese beetles.[3] Beetles have been detected in airports on the west coast of the United States since the 1940s.
The first Japanese beetle found in Canada was inadvertently brought by tourists to Yarmouth, 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.[5]
Japanese beetles have been found on the islands of the Azores since the 1970s.[6] In 2014, the first population in mainland Europe was discovered near Milan, Italy.[7][8] In 2017, the pest was detected in Switzerland, most likely having spread over the border from Italy. Swiss authorities are attempting to eradicate the pest.[9]
Only three were found in Washington State, USA, in 2020, but from late June to September 3, 2021, there were over 20,000 found in Grandview alone.[10]
Eggs are laid individually or in small clusters near the soil surface.[11] Within approximately two weeks, the ova hatch, the larvae feeding on fine roots and other organic material. As the larvae mature, they become c-shaped grubs, which consume progressively coarser roots and may do economic damage to pasture and turf at this time.
Larvae hibernate in small cells in the soil, emerging in the spring when soil temperatures rise again.[11] Within 4–6 weeks of breaking hibernation, the larvae will pupate. Most of the beetle's life is spent as a larva, with only 30–45 days spent as an imago. Adults feed on leaf material above ground, using pheromones to attract other beetles and overwhelm plants, skeletonizing leaves from the top of the plant downward. The aggregation of beetles will alternate daily between mating, feeding, and ovipositing. An adult female may lay as many as 40–60 ova in her lifetime.[11]
Throughout the majority of the Japanese beetle's range, its life cycle takes one full year; however, in the extreme northern parts of its range, as well as high-altitude zones as found in its native Japan, development may take two years.[12]
Phenological models might be useful in predicting the timing of the presence of larvae or adults of the Japanese beetle. Model outputs can be used to support the timely implementation of monitoring and control actions against the pest, thus reducing its potential impact.[13][14]
Owing to their destructive nature, traps have been invented specifically to target Japanese beetles. These comprise 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; instead, they land on plants in the vicinity and cause more damage along the flight path and near the trap than may have occurred if the trap were not present.[15][16]
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 two to four years to establish maximal protection against larval survival, expanding through the soil through repeated rounds of infection. Control programs based on milky spore disease have been found to work most efficiently when applied as large-scale treatment programs, rather than by isolated landowners. Bacillus thuringiensis is also used to control Japanese beetle populations in the same manner.[3]
On field crops such as squash, floating row covers can be used to exclude the beetles, but this may necessitate hand pollination of the flowers. Kaolin sprays can also be used as barriers.
Research performed by many US extension service branches has shown that pheromone traps attract more beetles than they catch; under favorable conditions, only up to three quarters of the insects attracted to a trap will be captured by it.[3][17] 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.
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,[17] or simply picking them off attractions such as rose flowers since the presence of beetles attracts more beetles to that plant.[18]
Several insect predators and parasitoids have been introduced to the United States for biocontrol. Two of them, the fly Istocheta aldrichi, a parasite of adult beetles, and the solitary wasp Tiphia vernalis, a parasite of larvae, are well established with significant but variable rates of parasitism. Tiphia vernalis reproduces by locating beetle grubs through digging, and on finding one, it paralyzes it with a sting and lays an egg on it; on hatching, the wasp larva consumes the grub. Istocheta aldrichi instead seeks out adult female beetles and lays eggs on their thoraxes, allowing its larvae to burrow into the insect's body and kill it in this manner. A female I. aldrichi can lay up to 100 eggs over two weeks, and the rapidity with which its larvae kill their hosts allows the use of these flies to suppress beetle populations before they can themselves reproduce.[3][19][20]
Soil-dwelling nematodes are known to seek out and prey on Japanese beetle grubs during the subterranean portion of their life cycle by entering larvae and reproducing within their bodies. Varieties that have seen commercial use as pest control agents include Steinernema glaseri and Heterorhabditis bacteriophora.[3]
While the larvae of Japanese beetles feed on the roots of many genera of grasses, the adults consume the leaves of a much wider range of hosts, including these common crops:[5] bean, cannabis, strawberry, tomato, pepper, grape, hop, rose, cherry, plum, pear, peach, raspberry, blackberry, corn, pea, okra, and blueberry.
Japanese beetle larva (grub)
Japanese beetle pupa
Japanese beetle adult
Adult Japanese beetles feeding on peach tree
Feeding, Ottawa
Japanese beetle feeding on calla lily, Ottawa, Ontario, Canada
{{cite news}}: CS1 maint: location (link) The Japanese beetle (Popillia japonica) is a species of scarab beetle. The adult measures 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, has iridescent copper-colored elytra, and a green thorax and head. It is not very destructive in Japan (where it is controlled by natural predators), but in North America and some regions of Europe, it is a noted pest to roughly 300 species of plants, including rose bushes, grapes, hops, canna, crape myrtles, birch trees, linden trees, and others.
The adult beetles damage plants by skeletonizing the foliage (i.e., consuming only the material between a leaf's veins) as well as, at times, feeding on a plant's fruit. The subterranean larvae feed on the roots of grasses.
