Bryan McAllister’s personal reference notebook
July 30, 2026Short & citedBlog
Civic Viewpoint.
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Kept by Bryan McAllister — short guides, clear facts, and the Canadian angle when it matters.
Field Notes • Insect

Japanese Beetle

The Japanese beetle (*Popillia japonica*) is a species of scarab beetle native to Japan and invasive in parts of North America and other regions.

Updated July 30, 20261 min readCited sources

The Japanese beetle is an invasive scarab beetle native to Japan. It is a regulated plant pest in Canada, known for damaging plants and lawns.

What it is

Japanese beetles are metallic green and copper-coloured scarab beetles native to Japan. First detected in North America in 1916, they are now considered invasive in parts of the continent, including Canada.

Why it matters

Adult beetles feed on leaves, flowers, and fruit of many plants, while larvae (grubs) feed on grass roots. This can damage lawns, turf, ornamentals, and agricultural crops. Canada classifies the Japanese beetle as a regulated invasive plant pest.

Key details

The species has one generation per year. Eggs hatch in about two weeks, grubs feed through summer and overwinter in soil, then pupate in spring. Adults emerge in late June or early July and are active during warm months.

In short

  • Japanese beetle is an invasive scarab beetle native to Japan.
  • Adults feed on leaves and flowers; larvae feed on grass roots.
  • One generation per year; most of life spent underground as a grub.
  • Canada regulates it as an invasive plant pest.
Canadian angle

Japanese beetle is a regulated invasive plant pest in Canada, with federal guidance focused on detection, containment, and management.

Quick questions

What is a Japanese beetle?
A Japanese beetle is a scarab beetle species (*Popillia japonica*) native to Japan and invasive in parts of North America. Adults feed on plant leaves and flowers, while larvae are soil-dwelling grubs that feed on roots.
Are Japanese beetles invasive?
Yes. Japanese beetles are considered invasive in North America, and Canadian federal sources describe them as an invasive plant pest.
How to get rid of Japanese beetles?
Common controls include hand-picking adults, using physical barriers such as netting, and applying approved insect or grub treatments at the correct life stage. Timing matters because adults and grubs are controlled differently.

Sources

  1. Canadian Food Inspection Agency — https://inspection.canada.ca/en/plant-health/invasive-species/insects/japanese-beetle/japanese-beetle-bc/fact-sheet?wbdisable=true
    Supports: Japanese beetle is an invasive plant pest first introduced to eastern North America from Japan in 1916.
  2. Canadian Food Inspection Agency — https://inspection.canada.ca/en/plant-health/invasive-pests-and-plants/insects/japanese-beetle/fact-sheet
    Supports: Life cycle details including wintering in soil, larval instars, and adult emergence in late June or early July.
  3. University of Wisconsin–Madison Extension — https://hort.extension.wisc.edu/articles/japanese-beetle/
    Supports: Native range, introduction to the U.S., one generation per year, egg-laying, larval feeding, and pupation timing.
  4. Minnesota Department of Natural Resources — https://www.dnr.state.mn.us/invasives/terrestrialanimals/japanese_beetle/index.html
    Supports: Three main life stages, adult emergence, feeding period, and egg-laying timing.
  5. University of Massachusetts Amherst — https://www.umass.edu/agriculture-food-environment/landscape/fact-sheets/japanese-beetle
    Supports: Japanese beetle is an invasive insect native to Japan and introduced to the United States in 1916.
  6. University of Minnesota Extension — https://extension.umn.edu/yard-and-garden-insects/japanese-beetles
    Supports: Adult and grub feeding habits, overwintering behavior, and seasonal activity.