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Grape (Table)

Identifying Caterpillars and Their Damage—Bloom and Veraison

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  • Omnivorous leafroller
  • Orange tortrix
  • Grape leaffolder
  • Western grapeleaf skeletonizer

Monitor for omnivorous leafroller, western grapeleaf skeletonizer, grape leaffolder, and orange tortrix (in coastal areas) from bloom through veraison. Continue monitoring for western grapeleaf skeletonizer and grape leaffolder until harvest.

Use the photos below to identify caterpillars and their damage. Also look for natural enemies of caterpillars. Names link to more information on identification and management.

Click on photos to enlarge
Omnivorous leafroller and orange tortrix Bloom damage Veraison damage

Omnivorous leafroller larvae
Omnivorous leafroller
Identification tip: Larvae have a black or brown head capsule. Mature larvae are cream to brownish green with whitish slightly convex tubercles on the top of the abdomen.

Silken nests made by larvae of the omnivorous leafroller, Platynota stultana, and their feeding damage on developing grape flowers.
Identification tip: Omivorous leafroller and orange tortrix both make silken nests on grape flowers.

Damage to grapes in veraison period by omnivorous leafroller
Identification tip: Rotting and raisining (drying up) of Thompson seedless grapes following chewing damage by omnivorous leafroller larvae.

Orange Tortrix Larvae
Orange tortrix
The larva is straw-colored with a brown head and prothoracic shield.

Orange tortrix larval feeding damage
Identification tip: Berries and stems damaged by orange tortrix have dry-calloused surfaces.
Grape leaffolder Bloom damage Veraison damage
A grape leaf curled and tied together with silk by the larva of a grape leaffolder, Desmia funeralis.
Grape leaffolder
Identification tip: Mature larvae are translucent-greenish with small black spots located above the second pair of legs, distinguishes later larvae from omnivorous leafroller.

Grape leaffolder larvae
Identification tip: Grape leaffolder larvae curl leaves and tie them together with silk.

No photo available.
Western grapeleaf skeletonizer Bloom damage Veraison damage

Pale, scraped surface of a grape leaf fed upon by larvae of western grapeleaf skeletonizer, Harrisina brillians.
Western grapeleaf skeletonizer
Identification tip: Feeding by larvae of western grapeleaf skeletonizer leaves the surface of foliage pale and scraped. The fourth- and fifth-instars are yellow with two purple and several blackish bands.


Typical damage by first-geneation grapeleaf skeletonizer
Typical damage by first-generation western grapeleaf skeletonizer on lower shaded leaves of grapevine.

Continued feeding bye western grapeleaf skeltonizer
Continued feeding by western grapeleaf skeletonizer leaves the surface of foliage pale and  scraped.
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