All about them
Gypsy moth undergoes four developmental life stages; these are the egg, larva (caterpillar), pupa, and adult. Gypsy moth females lay between 500 to 1,000 eggs in sheltered areas such as underneath the bark of trees. The eggs are covered with a dense mass of tan or buff-colored hairs. The egg mass is approximately 1.5 inches long and 0.75 inches wide. The eggs are the overwintering stage of the insect. Eggs are attached to trees, houses, or any outdoor objects. The eggs hatch in spring (April) into caterpillars.
Gypsy moth caterpillars are easy to identify, because they possess characteristics not found on other leaf-feeding caterpillars. They have five pairs of blue dots followed by six pairs of red dots lining the back. In addition, they are dark-colored and covered with hairs. Young caterpillars primarily feed during the day whereas the older caterpillars feed at night. When present in large numbers, the older caterpillars feed day and night. Young caterpillars spread to new locations by crawling to the tops of trees, where they spin a silken thread and are caught on wind currents. Older caterpillars are approximately 1.5 to 2.0 inches long. Gypsy moth caterpillars do not produce a web, which distinguishes it from web-making caterpillars such as the Eastern tent caterpillar, Malacosoma americanum and the fall webworm, Hyphantria cunea. The Gypsy moth larval stage lasts approximately seven weeks.
Gypsy Moth Control
- Keep your yard as clean as possible. Remove discarded items, dead branches, stumps, etc., where the adult female moth is likely to lay egg masses. Destroy any egg masses that are found.
- The Gypsy Moth Trap is used to monitor the moth population and may also prevent male moths from homing in on females.
- Tanglefoot Pest Barrier or Sticky Tree Bands can be placed around tree trunks to help curtail the caterpillars movement into and out of the tree canopy.
- Apply Bacillus thuringiensis, var. kurstaki or Monterey Garden Insect Spray (Spinosad) to the leaves of trees to kill gypsy moth caterpillars. For best results, sprays must be applied when caterpillars are young, less than one inch long. In instances where populations are high, two (or more!) applications five days apart might be needed.
- Azatrol EC contains azadirachtin, the key insecticidal ingredient found in neem oil. This concentrated spray disrupts growth and development of pest insects and has repellent and anti-feedant properties. Best of all, it’s non-toxic to honey bees and many other beneficial insects.
- Least-toxic botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.
No. There is more than one kind of gypsy moth, determined by where they came from. The traps that we put out will attract all gypsy moths. Most of the gypsy moths caught in the United States are from the European (North American) strain, but occasionally an Asian Gypsy Moth is captured. The Asian Gypsy moth is a larger concern because the females are able to fly, so the population could spread much faster. In addition,
they have a broader range of host plants that they will feed on than the European moth. Both types of Gypsy moths look the same.
European Gypsy moths are introduced to our state by people. Usually they come from states that are generally infested with the insect. The following states have some or all their counties in the APHIS quarantine: Connecticut, Delaware, Illinois, Indiana, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia, and Wisconsin. Gypsy moth introduction occur when some life stage of the moth (usually an egg mass or pupae) arrive attached to an outdoor household article such as lawn furniture or on a vehicle.
People moving to the state and tourists are normally the source of these introductions. The Asian Gypsy moth is rarely found in the United States, but is usually moved here on large vessels carrying cargo across the ocean from Asia.
Gypsy moth caterpillars feed mostly on deciduous trees and shrubs. When an infestation progresses, serious defoliation may occur and repeated defoliation may kill the trees. Equally offensive are the thousands of caterpillars and their droppings in residential areas and around home sites. The Asian Gypsy moth feeds on a much broader range of host plants than the European Gypsy moth.
There are dozens of common species of moths in this area. Identification of a specific species, particularly one as uncommon as a gypsy moth, requires careful examination of wing patterns, antenna and other features by a trained professional. Sometimes the use of a microscope or other visual aid is required. If you feel certain that you have seen a gypsy moth you should capture one (more if possible) and bring them to the
Idaho Department of Lands office for positive identification.
No. The baits in the traps only attract gypsy moths, and they are not harmful to people or pets.