Popillia japonica
In 3 days ~40% in a week ~70%
The Japanese beetle (Popillia japonica) is a species of scarab beetle. Due to the presence of natural predators, the Japanese beetle is not considered a pest in its native Japan. In North America and some regions of Europe, it is a noted pest to roughly 300 species of plants. Some of these plants include roses, 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.
English entomologist Edward Newman described the Japanese beetle in 1841. Adults of P. japonica measure 15 mm (0.6 in) in length and 10 mm (0.4 in) in width, with iridescent, copper-colored elytra and a green thorax and head. A row of white tufts (spots) of hair projects from under the wing covers on each side of the body. Males are slightly smaller than females. Grubs are white and lie in curled positions. A mature grub is roughly 1 in (2.5 cm) long.
Popillia japonica is native to Japan, and is an invasive species in North America... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Acadia National Park | 🇺🇸 United States | |
| 2 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 3 | Shenandoah National Park | 🇺🇸 United States | |
| 4 | Congaree National Park | 🇺🇸 United States | |
| 5 | Point Pelee National Park | 🇨🇦 Canada |
Possible
About 20% of wildlife watchers report a Japanese Beetle sighting in Shenandoah National Park on a given day, based on 65 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 53rd most-seen of the 723 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
July and August
In those months about 30% of wildlife watchers report a Japanese Beetle in Shenandoah National Park on a given day, against under 5% in October to May, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Japanese Beetle sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
3rd of 5
Of the 5 parks where we can rate Japanese Beetle sightings, Shenandoah National Park ranks 3rd at about 20%. The best odds are in Acadia National Park (United States, about 30%) and Great Smoky Mountains National Park (United States, about 20%).
Same family: Scarabaeidae
The closest relatives of the Japanese Beetle that you can see in Shenandoah National Park (family Scarabaeidae, Scarabs) are Common Green June Beetle (about 20%), Eastern Hercules Beetle (about 10%) and Grapevine Beetle (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Japanese Beetle is recorded against all the insects logged in Shenandoah National Park (65 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
