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Alameda County, CA,

Cathy Roache
Acting County Agricultural Commissioner / Sealer
Agriculture / Weights & Measures

Pest Exclusion

Gypsy Moth

Photo shows a Gypsy Moth egg mass on a tree.
Gypsy Moth
egg mass
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Photo of a gypsy moth caterpillar with red spots on its back.
Inspecting outdoor household articles for Gypsy Moth life stages
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Photo of a gypsy moth caterpillar with red spots on its back.
Gypsy Moth caterpillar
Enlarge Photo
Photo of a gray-brown colored male moth and white colored female moth.
Gypsy Moths
male and female
Enlarge Photo

The Gypsy Moth is one of the most damaging leaf-eating pests of trees and plants. The pest is prominent and is established in the Eastern United States, Canada and parts of Europe. A Federal-Domestic quarantine has been issued to control the spread of these pests by requiring the inspection of all outdoor household articles moved from infested areas into non-infested areas. Gypsy Moth life stages, with the egg mass stage being the most common, can be found on outdoor household articles such as BBQ grills, outdoor furniture, bicycles and children's play structures as well as trees and logs.

The egg mass is light brown, covered with yellowish hairs and is approximately 1 inch long and 34 inches wide. Each egg mass contains approximately 1,000 eggs. Caterpillars are gray, with red and blue dots on their backs and are from 1 12 to 2 12 inches in length. The female moth is white, has a 2 inch wingspread and is unable to fly. The male moth is gray-brown and has a 1 12 inch wingspread. The pests do not feed in the moth stage, but only mate and lay eggs.

Upon entry into the state of California, a Gypsy Moth quarantine notice is issued by the California Department of Food and Agriculture border stations to new California residents relocating from Gypsy Moth infested areas. Our staff completes inspections of all outdoor household articles that have been quarantined upon arrival at the new residence.

For more information on the Gypsy Moth Program, please call (510) 670-5158.

In addition to our Gypsy Moth quarantine state inspection program, we place and monitor Gypsy Moth traps throughout Alameda County, under our Pest Detection Program. Visit our Pest Detection Program or call (510) 670-5156.

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