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Grapeleaf Skeletonizer

Harrisina americana[3]

The grapeleaf skeletonizer is a small black moth with an orange collar whose yellow, black-spotted caterpillars feed in a row, side by side, on the undersides of grape and Virginia creeper leaves, skeletonizing them.[1][2]

Group
Insect
Order
Lepidoptera
Family
Zygaenidae
US records
35 states
Sources
3 cited
Updated
2026-10-16
Grapeleaf skeletonizer moth, black with an orange collar, on a leaf
Grapeleaf skeletonizer moth, black with an orange collar, on a leaf. (c) Adrienne van den Beemt, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Common questions
  9. Sources

How to identify it

  • Adults are small, narrow-winged, uniformly black moths with a yellowish or orange collar and a fan-shaped tuft at the tip of the upcurled abdomen; wingspan is about 7/8 to 1 1/8 inches (22 to 28 mm).[1][2]
  • Caterpillars are yellow with black spots or bands, four black bumps on each segment, and a little over 1/2 inch long when grown.[1][2]
  • Eggs are lemon yellow and laid in clusters on leaf undersides.[1][2]

Look-alikes

Look-alikeHow to tell them apart
Western grapeleaf skeletonizerA very similar, slightly larger species that replaces it in the West.[1][2]
Yellow-collared scape mothAlso black with a yellow collar but thicker-bodied, with larger, partly clear hindwings and no abdominal tuft.[1]

Where it lives

Widespread in the eastern half of the United States, including all of Florida except possibly the Keys.[1][2]

US map: public records from 35 states since 1990 (GBIF).

Biology and life cycle

It overwinters as a pupa in a cocoon in debris on the ground; adults emerge in late spring and lay eggs in clusters under leaves.[1][2]

There are two generations a year in Virginia, and moths fly in Florida from March to September or later.[1][2]

Larvae feed in groups at first, then disperse as they mature.[1]

Damage and signs

  • Young larvae skeletonize leaves, leaving brown patches; older larvae eat whole leaves down to the large veins.[1][2]
  • Native hosts are wild grapes and Virginia creeper; among cultivated grapes it prefers tender, choice varieties, and it is mostly a problem on home grapevines rather than sprayed vineyards.[1]

Health risk

None to people or pets.[1][2]

Control

Sanitation

Because they spin cocoons in leaves and trash under the vines, cleaning up that debris helps.[1]

Traps and physical control

Handpick the caterpillar clusters as soon as you see them, while each egg cluster's larvae are still together in one group.[1]

Biological control

Bacillus thuringiensis controls the caterpillars.[1]

Common questions

What are the yellow caterpillars lined up on my grape leaves?
Grapeleaf skeletonizer larvae, which feed side by side in a row.[1][2]
How do I control them?
Handpick the groups early or use Bt.[1]
Do they eat Virginia creeper?
Yes; Virginia creeper is a native host.[1]

Sources

  1. University of Florida IFAS Extension (EDIS, Featured Creatures), “Grapeleaf Skeletonizer, Harrisina americana (EENY-191).” ask.ifas.ufl.edu/publication/IN348 (accessed 2026-10-16)
  2. Virginia Tech Department of Entomology (Virginia Cooperative Extension), “Grapeleaf skeletonizer, Harrisina americana (Virginia Fruit pages, from Va. Coop. Ext. Serv. 444-567).” www.virginiafruit.ento.vt.edu/grapeskel.html (accessed 2026-10-16)
  3. iNaturalist, “Harrisina americana taxon page (order and family).” www.inaturalist.org/taxa/126905 (accessed 2026-10-06)

Updated 2026-10-16. Built from sourced records. Spot an error? Tell us.