Spongy Moth

• Egg masses (late summer, winter and spring)
  • Female moths attach egg masses to trees, stones, walls, logs, and household items, such as patio furniture, children’s toys, and lawn equipment.
  • Each egg mass contains up to 1,000 eggs and is covered with buff or yellowish “hair” (from the abdomen of the female).
  • Egg masses are about 1-1/2 inches long and 3/4-inch wide on average.
• Caterpillars (spring)
  • Newly hatched caterpillars are black and hairy.
  • Older caterpillars are a mottled yellow to gray color with tufts of bristle-like hairs. They also have a distinctive color pattern along their backs with five pairs of blue dots followed by six pairs of red dots.
  • They are about 1-1/2 to 2-1/2 inches long when fully grown.
• Adult moths (summer)
  • Male moths are brown with a darker brown pattern on their wings and have a 1-1/2-inch wingspan.
  • Females are nearly white, slightly larger, and have a 2-inch wingspan but do not fly. Their wings are marked with dark, saw-toothed patterns.
• Defoliated trees
  • Infested trees may be partially or completely bare of leaves.
  • A heavily infested forest will have a barren, wintry look in the middle of the summer.

View photos of spongy moth and the damage it causes:

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Show Info

1st instar larva emerging from egg mass. USDA Photo.

Spongy Moth Pupae. Photo by PA Department of Conservation and Natural Resources-Forestry Archive, Bugwood.org

Spongy Moth Larva. USDA Photo by John H. Ghent, Forest Service, Bugwood.org

Female spongy moths laying egg masses. Photo by Milan Pernek, Forestry Research Institute, Bugwood.org

Defoliation, Photo by Haruta Ovidiu, University of Oradea, Bugwood.org

Defoliated oak branch, Photo by Louis-Michel Nageleisen, Département de la Santé des Forêts, Bugwood.org

Adult Male Spongy Moth, USDA Photo by John H. Ghent, Forest Service

The spongy moth is a hitchhiker. People can unknowingly spread this pest when they move vehicles and other outdoor items that have spongy moth egg masses attached. Here's what you can do to prevent spongy moth from spreading:

• Look for spongy moth egg masses on trees, lawn furniture, fences, walls, outdoor items, and report them to Federal or State agriculture officials if you are not in a quarantine area.
• Know and follow any quarantines regulations in your area, especially if you are relocating. Check the Regulatory Information panel below for more information.
• Before moving or traveling out of an infested area, check for the spongy moth egg masses, caterpillars and adults. This is required by Federal law in many areas. See details below under "Your Move Spongy Moth-Free."
• Buy local firewood and burn it on site. Do not move firewood.  
• Comply with Federal, State, and local spongy moth restrictions.
• Cooperate with agriculture officials surveying for this pest. They may ask for access to your property to place and check insect-monitoring traps.

Your Move Spongy Moth-Free

Per USDA requirements, you must inspect and remove spongy moth egg masses from household goods before moving from a location within a spongy moth quarantine area to a location outside the quarantine area.

You may face penalties if you are required to inspect but fail to do so. Fortunately, it's easy to meet the requirements:

1. Check the map to find out whether you live in a quarantine area.
2. Look for spongy moth egg masses and other life stages (see above photos) on all outdoor household items.
   • Use and print the self-inspection checklist (2.85 MB) or the online checklist option.
   • If you're moving between April and August, complete the inspection on moving day, if possible.  
   • If you cannot complete the inspection on moving day, you must protect the items from infestation. Seal them under a tarp or keep them indoors or in a closed moving truck.
3. Remove and destroy any egg masses or life stages you find.
   • Scrape them off with a putty knife, stiff brush, or similar hand tool.
   • Dispose of egg masses and other life stages in a container of hot, soapy water, or place them in a plastic bag, seal it, and set it in the sun.
4. Check each item off on your checklist (2.85 MB) as you go and complete the requested information.
   • If a qualified certified applicator performs the inspection, be sure you get a copy of the completed, signed checklist.
5. Keep a copy of the completed checklist in the vehicle moving the goods. This is your official certificate of inspection. USDA or State officials may request it during your trip.
   • If you are not driving, provide a copy to the driver. 
      

Note: If you do not live in a quarantine area, this law does not apply to you.

Questions? Contact your State plant regulatory official or State plant health director.

Homeowners in spongy moth quarantine areas can contact their county Extension office to ask about spongy moth control options. Individuals in non-quarantine areas, should contact their State plant health director or State plant regulatory official to report spongy moth.