United States Department of Agriculture

Animal and Plant Health Inspection Service Pest Alert Plant Protection and Quarantine Asian Gypsy Moth

The Asian gypsy moth (AGM, including Lymantria dispar asiatica, Lymantria dispar japonica, Lymantria albescens, Lymantria umbrosa, and Lymantria postalba) is an exotic pest not known to occur in the United States. Although in many ways similar to the European gypsy moth, AGM larvae feed on a much broader range of plant species, covering over 100 botanical families. This broad range of possible host plants, combined with the female’s ability to fly long distances, could allow AGM to spread rapidly. Large infestations of AGM can completely defoliate trees, leaving them Asian gypsy moth adults weak and more susceptible to disease or attack by other insects. If defoliation is repeated for 2 or more years, it can Ships infested with AGM egg masses lead to the death of large sections of from ports in eastern Russia probably forests, orchards, and landscaping. Any introduced the pest to North America introduction and establishment of AGM while visiting ports on the West Coast. in the United States would pose a major Scientists believe that, while the ships threat to the environment and the were docked, larvae hatched from the urban, suburban, and rural landscapes. eggs and were blown ashore. USDA and State officials eradicated these Asian gypsy moth larva (above) and eggs (below) Since 2009, the U.S. Department of infestations in the Pacific Northwest (John Ghent, USDA Forest Service, Bugwood.org) Agriculture (USDA), in partnership through trapping and treatment with the Canadian Food Inspection activities. Agency, has worked with foreign trading present and what followup actions may partners to monitor populations of AGM In 1993, another infestation, this be needed to address them. and inspect ships before they leave to time in Sunny Point, NC, occurred certify that they are free of AGM life after moths emerged from a ship Several USDA pest risk assessments stages. Ships are also inspected for carrying infested cargo containers over the years have concluded that, AGM when they arrive at U.S. ports. from Germany and then flew into the because of similarities between Asian Although these preventive measures surrounding area. AGM was not known and North American ecosystems, are effective, occasional introductions to occur in Europe until tracebacks of left unaddressed, the AGM has great of AGM have occurred. When AGM this introduction provided evidence potential for colonization in North is detected, USDA works with other of other populations there. Between American forests. Federal and State agencies to evaluate 1991 and 2014, AGM was detected and the infestation and take appropriate eradicated on at least 20 occasions in Potential Damage actions to keep it from spreading. locations across the United States. If established in the United States, Background The most recent AGM detections AGM could cause serious, widespread occurred in 2015 when male moths damage to our country’s landscape and AGM was first identified in North were caught in survey traps: 10 moths natural resources. Each AGM female America in late 1991 near the Port in Washington State, 2 moths in can lay hundreds of eggs in fuzzy egg of Vancouver in British Columbia, Oregon, 1 moth in Georgia, and 1 moth masses that, in turn, yield hundreds of Canada. Moths were discovered shortly in South Carolina. Ongoing surveys in voracious caterpillars that may feed on thereafter in Washington, Oregon, and those States and Oklahoma will help hundreds of tree and shrub species. British Columbia. determine whether infestations are AGM caterpillars can defoliate plants at an alarming rate. This defoliation AGM eggs begin hatching into caterpillars ships and cargo undergo another can severely weaken trees and shrubs, in the spring. All of the damage caused inspection to ensure that AGM is not killing them or making them more by the AGM happens during the present. These protective measures are susceptible to diseases and other pests caterpillar stage, as the insects feed highly effective but, on rare occasions, and destroying habitats for mammals on leaves during this active period of AGM introductions do occur. A robust and birds. Caterpillar silk strands, growth. Once AGM caterpillars stop survey program at and near ports droppings, destroyed leaves, and dead feeding, they enter the pupal stage. of entry helps detect any possible moths would also be a nuisance in This stage typically begins in June or introductions at an early stage—when homes, yards, and parks. July. Because egg hatch and pupation eradication efforts are most effective depend on weather and temperature, and least costly. Comparing Gypsy Moth Pests they may occur earlier or later in different areas. Adult moths emerge What You Can Do The AGM is similar to the European from their dark-brown pupal cases in gypsy moth found in the northeastern 10 to 14 days. Adult males have You can support efforts to detect and United States and southeastern Canada. grayish-brown wings and a wingspan manage AGM by: Like the European gypsy moth, AGM of 1 ½ inches. Adult female moths are • Reporting any findings of egg masses prefers forest habitats and can cause white and larger, with wingspans of on trees, lawn furniture, fences, serious defoliation and deterioration of 3 ½ inches or more. walls, or elsewhere to Federal or trees and shrubs. The European gypsy State agriculture officials. moth has more than 300 known host AGM do not feed in the moth stage plants but prefers oak. The AGM has (which lasts 1 to 3 weeks); they • Cooperating with any restrictions in a much broader host range, including only mate and lay eggs. Eggs are your local area that might be imposed larch, oak, poplar, alder, willow, and laid between June and September, because of an AGM detection. some evergreens. depending on weather and location. • Allowing authorized agricultural The eggs remain dormant during the workers access to your property In the eastern United States, European winter and develop and hatch the to place and inspect insect- gypsy moths defoliate an average of following spring. monitoring traps. 700,000 acres each year, causing millions of dollars in damage. If AGM How AGM Can Spread To learn more, contact your: were to become established in our • Local Extension office country, the damage could be even AGM infestations spread in several www.nifa.usda.gov/Extension more extensive and costly. ways. Adult female moths may fly to previously uninfested areas to lay eggs. • State Plant Regulatory Official Unlike the flightless female European Or, newly hatched AGM caterpillars www.nationalplantboard.org/ gypsy moths, AGM females are active may climb to tree crowns, where the member fliers. Their ability to fly long distances wind picks up their silken threads and • Nearest USDA Animal and Plant makes it probable that AGM could carries them to other areas. Health Inspection Service office quickly spread throughout the United www.aphis.usda.gov/planthealth/ States. In contrast, the European gypsy In addition, people can inadvertently sphd moth has taken more than 140 years transport egg masses or pupae. AGM (since 1869) to spread throughout the egg masses tolerate extremes in United States from the Northeast to the temperature and moisture and travel Southeast and the Midwest. well on logs, lawn furniture, nursery stock, pallets, shipping containers, and Life Stages the hulls and rigging of ships.

The AGM matures through four life Protecting the Country stages: egg, larva (caterpillar), pupa From AGM (cocoon), and moth. AGM egg masses may be found on tree trunks, limbs, The first line of defense against AGM or leaves, as well as on stones, walls, is USDA’s work to prevent this pest logs, lawn furniture, and other outdoor from reaching the United States. In objects. Each egg mass can contain partnership with Canada, the USDA hundreds to more than 1,000 eggs. The works with China, Japan, South mass is covered with buff or yellowish Korea, and Russia to make sure AGM fuzz from the abdomen of the female. population levels are monitored at While the velvety egg masses average APHIS 81-35-027 and near ports. Ships and cargo Issued April 2016 1 ½ inches long and three-fourths of headed for the United States are an inch wide, they are often as small inspected for AGM and certified as USDA is an equal opportunity provider, as a dime. pest-free before departing. On arrival, employer, and lender.