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July 26, 2026Sources cited
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Gypsy moth

The gypsy moth (*Lymantria dispar*) is a species of moth known for its caterpillars, which can defoliate a wide range of trees and shrubs.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The gypsy moth (Lymantria dispar) is a species of moth known for its caterpillars, which can defoliate a wide range of trees and shrubs. It is native to parts of Europe and Asia and has become an invasive pest in North America and other regions. The common name has been formally replaced by spongy moth in North America.

Taxonomy and naming

Lymantria dispar is a moth in the family Erebidae. The species was long called the gypsy moth, but the preferred common name in North America is now spongy moth.

Description and life cycle

Adults and larvae vary by strain and sex, with females of the European strain being flightless. The species typically completes one generation per year, with eggs overwintering before larvae hatch in spring.

Distribution and invasion history

The species is native to parts of Europe and Asia and was introduced to North America in the 1800s. It is now established in much of northeastern North America and has also been reported in parts of Europe outside its native range.

Ecological impact

Gypsy moth caterpillars feed on leaves of many broadleaf trees and shrubs and can cause severe defoliation during outbreaks. Repeated defoliation can weaken trees and, in some cases, lead to tree mortality.

Key facts

  • The species is a major defoliator of hardwood trees and shrubs.
  • Its larvae, or caterpillars, feed on many host plants, including oaks.
  • It was introduced to North America in the 19th century and spread widely.
  • The European strain has flightless females, while the Asian strain includes flying females.
  • It is considered an invasive forest pest in parts of North America.
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Canadian context

The species is established in parts of Canada and is monitored as an invasive forest pest because its caterpillars can defoliate hardwood trees and affect forests and ornamental plantings.

Frequently asked questions

What is the gypsy moth now called?
In North America, the preferred common name is *spongy moth*.
What does the gypsy moth eat?
Its caterpillars feed on the leaves of many trees and shrubs, especially hardwoods such as oak.
Where is the gypsy moth native to?
It is native to parts of Europe and Asia.
Why is it considered a pest?
The larvae can defoliate trees over large areas, causing forest and landscape damage.
When was it introduced to North America?
It was introduced in the 1800s, with sources citing 1868 or 1869.

References

  1. Natural Resources Canadahttps://tidcf.nrcan.gc.ca/en/insects/factsheet/9506
    Supports: Scientific name, pest status, native/introduced history, and host impact.
  2. Royal Horticultural Societyhttps://www.rhs.org.uk/biodiversity/gypsy-moth
    Supports: Current preferred common name spongy moth and tree-defoliation impact.
  3. Forest Researchhttps://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/gypsy-moth-lymantria-dispar/
    Supports: Defoliator status, distribution, and native range in Europe.
  4. National Invasive Species Information Centerhttps://www.invasivespeciesinfo.gov/terrestrial/invertebrates/spongy-moth
    Supports: Former common name, invasive spread, and threat to deciduous trees.
  5. Alaska Department of Fish and Gamehttps://www.adfg.alaska.gov/index.cfm?adfg=invasiveprofiles.gypsymoth_characteristics
    Supports: Life cycle, egg masses, larval development, and female flightlessness in the European strain.
  6. Food and Agriculture Organization of the United Nationshttps://www.fao.org/4/i0640e/i0640e10p.pdf
    Supports: Outbreak potential, host range, and differences between Asian and European strains.