Gypsy Moth

The caterpillars of this bug are leaf-eating machines!  They can totally strip every leaf from oaks (their favorite food) and many other tree species.  With so many trees in danger, we need a hero like Frankie Barker to protect them!  Check out the field guide below and then scroll to the bottom of the page to learn more!

Printable Field Guide: PDF

  • Late stages of the larvae (caterpillar) are usually about 2 inches long. They have a mottled yellow to gray pattern with tufts of bristle-like hairs and a unique color pattern of five pairs of blue dots followed by six pairs of red dots along their backs.  Photo Credit: Ferenc Lakatos, University of West-Hungary, Bugwood.org

  • Male gypsy moths (Lymantria dispar) are brown with a darker brown wing pattern, and have a 1.5 inch wingspan. Females are almost white, have dark saw-toothed patterns on their wings and are slightly larger.  Photo Credit: USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org

  • Male gypsy moths also have feathery antennae!  Photo Credit: Thérèse Arcand, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre

  • The female Gypsy moths do not fly, they crawl and lay eggs. Here we see an egg mass covered with "buff" or yellowish hair from the abdomen of the female. Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

  • Gypsy Moth (Lymantria dispar) egg masses are usually 1.5 inches long and about 0.75  inched wide. They can contain up to 1,000 eggs and are covered with "buff" or yellowish hairs.  Photo Credit: Pennsylvania Department of Conservation and Natural Resources - Forestry Archive

  • Gypsy Moth (Lymantria dispar) egg masses can be found between August and April. After eggs hatch in the spring, the caterpillars (larvae) feed on tree leaves.  Photo Credit: USDA Forest Service Region 8 Archive

  • The larvae grow in stages called "instars" and must molt in between each stage. Male gypsy moths have five instars and females have six. The larvae are what cause all the damage to the trees and can be found from May to June.  Photo Credit: USDA Forest Service Rocky Mountain Region Archive

  • After the final instar stage, the larvae transforms (pupates) before becoming an adult moth. Gypsy moth pupae can be found early to mid July.  Photo Credit: Pennsylvania Department of Conservation and Natural Resources

  • Here we see an adult male and female moth ready to reproduce late in July.  Photo Credit: Pennsylvania Department of Conservation and Natural Resources - Forestry Archive

  • Gypsy moths can feed on over 100 species of woody plants, but oak trees are its favorite. With over 50 species of Quercus in the U.S. alone, oak leaves come in many different shapes!  Photo Credit: Alice B. Russell, Department of Horticultural Science, NC Cooperative Extension Service, NC State University

  • Aspen is another favorite of the gypsy moth. The bigtooth aspen (Populus grandidenta) shown here has alternate, oval-like, shiny leaves with flattened bases attached to long stalk, making them easily ripple in the wind. As its name implies, it has "big teeth" on the edges of its leaves.  Photo Credit: David Lee, Bugwood.org

  • Gypsy moth also feeds on several types of birch trees. The outer bark of this paper birch (Betula populifolia) is smooth, thin and white. The inner bark is orange. The paper birch grows along stream banks, lakeshores, and on the moist slopes of hills.  Photo Credit: David Lee, Bugwood.org

  • Sweetgum is also preferred by gypsy moth. These trees can reach 100 feet tall, have 3-7 lobed, star-shaped leaves and a distinctive spiky fruit. Sweetgum leaves are green most of the year but can turn many different colors in the fall. Photo Credit: Michasia Harris, University of Georgia, Bugwood.org

  • Oaks tend to grow large and round, reaching heights of over 100 feet or more. Acorns are a sure sign you have spotted an oak tree.  Photo Credit: Allen Bridgman, South Carolina Department of Natural Resources, Bugwood.org

  • Keep alert for egg masses on trees, logs, stones, walls, and other object in the outdoors.  An egg mass can contain up to 1,000 eggs and is covered with fuzz. They average 1 1/2 inches long and 3/4 of an inch wide.  Photo Credit: Milan Zubrik, Forest Research Institute - Slovakia, Bugwood.org

  • Early second instar larvae with shot-hole damage on chestnut oak.  Photo Credit: John H. Ghent, USDA Forest Service, Bugwood.org

  • Gypsy moth larva feeding on leaves - Caught in the act! Photo Credit: Haruta Ovidiu, University of Oradea, Bugwood.org

  • Closeup of leaves that have been skeletonized by gypsy moth larvae.  Photo Credit: Louis-Michel Nageleisen, Département de la Santé des Forêts, Bugwood.org

  • Branch that has been completely defoliated by larval feeding.  Photo Credit: Landesforstpräsidium Sachsen Archive, Bugwood.org

  • An entire stand of trees can be defoliated by gypsy moth.  Photo Credit: Tim Tigner, Virginia Department of Forestry, Bugwood.org

  • Defoliated forested area in late spring.  Photo Credit: USDA APHIS PPQ Archive, USDA APHIS PPQ, Bugwood.org

  • Summer defoliation caused by an extensive gypsy moth infestation.  Photo Credit: USDA Forest Service Archive, USDA Forest Service, Bugwood.org

  • Gypsy moth defoliation of oaks and other broadleaf trees.  Photo Credit: William M. Ciesla, Forest Health Management International, Bugwood.org

  • Special color infrared aerial photos are taken to show heavy defoliation by the gypsy moth.  Photo Credit: William M. Ciesla, Forest Health Management International, Bugwood.org

  • Pheromone lure traps effectively capture male adult Gypsy moths. They aid in determining emergence of the moth in a specific area.  Photo Credit: Daniel Herms, The Ohio State University, Bugwood.org

  • Spray treatments are considered if gypsy moth populations are at damaging levels.  Photo Credit: John H. Ghent, USDA Forest Service, Bugwood.org

  • Gypsy moth populations can only reach outbreak levels where their preffered species are abundant; otherwise they crash because of starvation and disease.  Photo Credit: John H. Ghent, USDA Forest Service, Bugwood.org

  • Deer mice are an important native and natural enemy of gypsy moth.  Photo Credit: Bill Antrobius, USDA Forest Service, Bugwood.org

  • Spray treatments are considered if gypsy moth populations are at damaging levels.  Photo Credit: John H. Ghent, USDA Forest Service, Bugwood.org

Scientific Name: Lymantria dispar

Description: Male and female adult gypsy moths look very different.  Females are cream colored, cannot fly, and have black “v” shaped markings on their wings.  Males are small brown moths with big feathery antennae, and they fly in zig-zag patterns looking for females.  Gypsy moth larvae are black, furry caterpillars, with five pairs of blue dots and six pairs of bright red dots along their backs.  After they hatch in the spring, young caterpillars make silk threads which help them to be carried away by the wind to find new trees to eat.  Gypsy moth egg masses look like tan, fuzzy blobs, and are hidden in crafty places by gypsy moth females.  If you live in an area where gypsy moths live, be sure to check your outdoor toys for gypsy moth egg masses before you take them on a camping trip! 

 

Native Range: Europe, North Africa

 

Introduced Range: Connecticut, Delaware, Illinois, Indiana, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, Washington DC, West Virginia and Wisconsin, as well as across southern Canada.

Map courtesy of USDA APHIS

Establishment Suitability Map:

 

Map Courtesy of US Forest Service FHTET

 

Habitat: Gypsy moth is found in both urban areas and forests, but is a particular problem in hardwood forests.

 

Host Trees: Oaks are preferred, but hungry gypsy moth caterpillars can eat several hundred different tree species, including apple, alder, basswood, birch, hawthorn, poplar, sweetgum and willow.

 

The Facts: Gypsy moth caterpillars have huge appetites! About every ten years, gypsy moth populations grow very large and can completely strip trees of their leaves.  If they attack a tree for two or three years, it may die.  Gypsy moth caterpillars sometimes consume the leaves of hundreds of acres of forest at a time, destroying important timber and shade trees, and costing millions of dollars in damage.  Thousands of feeding caterpillars can cause allergic reactions in people and can make huge messes in yards.  Gypsy moth feeding is also bad for other forest animals, like birds, that make their homes in the trees too.  Fortunately, scientists have developed control methods to slow this bad guy down, and helpful natural enemies of the gypsy moth have spread to keep the hungry caterpillars in check.  In neighborhoods, the impact of gypsy moth can be reduced by hunting for and destroying egg masses in wintertime to make sure caterpillars don’t eat leaves in the spring.  Burlap hiding bands on tree trunks or certain insecticide treatments can be used to control caterpillars in the springtime.