Biological control of chestnut blight with hypovirulence: a critical analysis

Annu Rev Phytopathol. 2004;42:311-38. doi: 10.1146/annurev.phyto.42.040803.140325.


Most hypovirulence in the chestnut blight fungus, Cryphonectria parasitica, is associated with infection by fungal viruses in the family Hypoviridae. Hypovirulence has controlled chestnut blight well in some locations in Europe and in Michigan in the United States. In contrast, with few exceptions, biological control has failed almost completely in eastern North America. Therapeutic treatment of individual cankers is successful in most cases, but the success of hypovirulence at the population level depends on the natural spread of viruses. Characteristics of three interacting trophic levels (virus, fungus, and tree), plus the environment, determine the success or failure of hypovirulence. Vegetative incompatibility restricts virus transmission, but this factor alone is a poor predictor of biological control. Any factor reducing the rate of chestnut blight epidemics enhances hypovirus invasion. Overall, however, not enough is understood about the epidemiological dynamics of this system to determine the crucial factors regulating the establishment of hypovirulence in chestnut forests.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Aesculus / microbiology*
  • Animals
  • Ascomycota / virology*
  • Pest Control, Biological*
  • Plant Diseases / microbiology
  • Plant Diseases / virology*
  • RNA Viruses / pathogenicity
  • RNA Viruses / physiology*
  • Virulence