About the Gypsy Moth
The Gypsy Moth (GM) is native to Europe. It was first detected in the United States in 1869 in Massachusetts. Several Gypsy moth introductions have been detected and eradicated in California since the 1970’s. The Gypsy Moth is a dangerous pest because the caterpillars have voracious appetites for more than 500 species of trees and shrubs, posing a danger to North America’s forest habitats. The caterpillars defoliate, or strip the tree of leaves, which kills the tree and/or leaves it vulnerable to disease and other pests. The caterpillars feed mainly on hardwood trees, such as oaks, aspen, birch and willow. Native and common California species like Manzanita and western hemlock may also be at risk from GM.
What Does the Gypsy Moth Look Like?
Male Gypsy moths are brown with a darker brown pattern on their wings and have a one-and-a-half inch wingspan.
Females are slightly larger, with a two-inch wingspan, and nearly white with dark saw-toothed patterns on their wings.
The larva, or caterpillar, stage is the most destructive. Newly hatched caterpillars are black and hairy. Later stages of the larvae develop a mottled yellow to gray pattern with tufts of bristle-like hairs and a distinctive color pattern of five pairs of blue dots followed by six pairs of red dots along their backs.
What is the Gypsy Moth’s Life Cycle?
The GM matures through four life stages: egg, larva/caterpillar, pupa/chrysalis and adult moth. GM egg masses may be found on trees, stones, walls, logs, lawn furniture and other outdoor objects. Each egg mass may contain 100 to 1,000 eggs. The mass is covered with buff or yellowish fuzz from the abdomen of the female and averages about one-and-a-half inches long and about 3/4 of an inch wide.
GM development is dependent on weather and temperature. Eggs begin hatching into caterpillars in the spring. All of the damage caused by the GM happens during the caterpillar stage, as the insects feed on leaves during this active period of growth. GM caterpillars stop feeding when they enter the pupal stage, beginning in June or July. Adult moths emerge from the dark brown pupal cases in 10 to 14 days. European Gypsy Moths mate and lay eggs in the moth stage, which lasts one to three weeks. Eggs are laid between July and September, remain dormant during the winter, and hatch the following spring.
What Kind of Damage Can the Gypsy Moth Cause?
All of the damage caused by the GM is done during the caterpillar stage, as the insects feed on leaves during this active period of growth. Gypsy moth caterpillars feed on hundreds of kinds of plants and are capable of defoliating trees at an alarming rate. A single gypsy moth caterpillar can eat up to one square foot of leaves per day. When trees are repeatedly defoliated, they become more susceptible to other pests and diseases, leading to tree death and an increased potential for fire and erosion. Defoliation also destroys habitat for mammals and birds.
GM infestations spread in one primary way: through larval movement. Newly hatched caterpillars climb to tree crowns, where the wind picks up their silken thread and carries them to other areas.
In addition, people can inadvertently transport egg masses. GM egg masses can handle extremes in temperature and moisture and travel well on logs, lawn furniture, nursery stock, pallets, shipping containers and on the hulls and riggings of ships.
The Gypsy Moth prefers approximately 150 primary hosts but feeds on more than 500 species of trees and shrubs. Some of those include:
- Aspen
- Birch
- Cedar
- Cottonwood
- Fruit trees
- Larch
- Oak
- Poplar
- Willow
What Could That Damage Mean to the Economy?
This defoliation not only kills and weakens trees, but also damages the overall health of forests and destroys habitat for mammals and birds. Gypsy moth infestations affect recreational use of forests, parks and backyards. Swarms of caterpillars discourage tourism and many other outdoor activities. In urban areas, the economic impact includes clean-up costs, tree replacement costs and loss of property values.
Where is the Gypsy Moth Found in California?
Gypsy Moth was found in Ojai (Ventura County) in 2008 and an eradication program is underway there. GM is not known to be established in California.
What Can We Do?
People can take several actions to assist in the detection and management of this pest:
- Report any findings of egg masses on trees, lawn furniture, fences, walls or elsewhere on private property to Federal or State agriculture officials;
- Cooperate with any restrictions that might be imposed locally because of a GM detection; and
- Allow authorized agriculture workers access to property to inspect insect–monitoring traps.
Resources List [not a comprehensive list]
Gypsy Moth Pest Profile
California Department of Food and Agriculture
http://www.cdfa.ca.gov/phpps/PDEP/target_pest_disease_profiles/
gypsy_moth_profile.html
Gypsy Moth: Slow the Spread Fact Sheet
United States Department of Agriculture, Animal and Plant Health Inspection Service
http://www.aphis.usda.gov/publications/plant_health/content/printable_version/
fs_phgmprogress.pdf
Pest Tracker: European Gypsy Moth
National Agricultural Pest Information System
http://pest.ceris.purdue.edu/searchmap.php?selectName=ITAXAIA
European Gypsy Moth Background
United States Department of Agriculture, Animal and Plant Health Inspection Service
http://www.aphis.usda.gov/plant_health/plant_pest_info/gypsy_moth/egm-
background.shtml
