Biology and management of the horned oak gall wasp on pin oak

Eileen A. Eliason, Daniel A. Potter

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The horned oak gall wasp (Callirhytis cornigera) induces large, woody galls on twigs of oak; these galls can disfigure trees and result in extensive branch dieback. This paper reviews our recent research on the pest's biology and management on cultivated pin oaks (Quercus palustris) in Lexington, Kentucky, U.S., especially aspects that are of greatest relevance to tree care professionals. The gall wasp has alternating agamic (all female) and sexual generations that develop, respectively, in multi-chambered twig galls and single-chambered leaf galls along veins. Wasp development required about 33 months in twig galls and about 3 months in leaf galls. The number of gall wasps developing within twig galls ranged from 1 to 160, and was dependent on gall size. Numerous other insects, including parasitoids and inquilines, were found within the galls. Natural enemies accounted for high mortality of C. cornigera, especially in the leaf-galling generation where 70% to 80% of the larvae were parasitized. The dogwood borer (Synanthedon scitula) infested about 15% of the succulent 2- to 3-year-old twig galls. Adult S. scitula moths had a similar, bimodal emergence period regardless of whether they originated from dogwoods or horned oak galls. Insecticidal controls targeting the leaf galling stage of C. cornigera killed the pest, but also its parasitoids. Therefore, no reduction in the number of twig stem galls was achieved. Difficulties in managing this pest in outbreak situations are discussed.

Original languageEnglish
Pages (from-to)92-101
Number of pages10
JournalJournal of Arboriculture
Issue number2
StatePublished - 2001


  • Callirhytis cornigera
  • Cynipidae
  • Gall wasp
  • Pest management
  • Pin oak
  • Quercus palustris

ASJC Scopus subject areas

  • Forestry
  • Ecology


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