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Asian Lymantria dispar (Gypsy Moth)

Note: The common name of Lymantria dispar (gypsy moth) was discontinued on July 8, 2021 by the Entomological Society of America.

Research Issue

[photo:] Asian gypsy moths laying egg masses near lights on a Russian vessel while in port.Lymantria dispar is one of the most serious forest pests, capable of causing widespread outbreaks and tree mortality in the temperate northern hemisphere. The gypsy moth range in Eurasia is roughly between 60°N and 30°N but does extend further south (20° N) in the Far East.  There are two primary types of L. dispar, the ‘European’ and ‘Asian’. While both of these non-native pests can wreak havoc on forests, Lymantria dispar asiatic are considered a more serious threat as females are capable of flying long distances, unlike their flightless female European counterparts, thus making it probable that L. dispar asiatic could spread more rapidly throughout the United States.

Multiple introductions of L. dispar asiatic strains have occurred from egg masses on ships and cargo entering ports in western North America, and from pupae on military equipment entering the eastern United States. Most introductions have prompted eradication programs, the largest of which occurred in 1992 and 1994. 

The biggest concern over the introductions of L. dispar is the presence of flight-capable females which have the potential to increase the rate of spread and complicate procedures for detecting and delimiting isolated populations. In addition, there are other concerns because of the wide variation in behavioral, physiological, and genetic characteristics exhibited by the gypsy moth across its geographic range.  For example, some L. dispar strains possess traits that make them more threatening to North American forests, including a broader host range, shortened egg chill requirements, and female attraction to lights that results in egg deposition on vehicles or cargo. Since the mid-1990s, quarantine-based proactive research has been conducted on L. dispar from Eurasia.

Our Proactive Research Done Under Quarantine

  • Last modified: July 16, 2021