Irreversible Pathogenitätsverminderung bei Endothia parasitica durch übertragbare Hypovirulenz

Irreversible reduction in pathogenicity of Endothia parasitica through transmissible hypovirulence . Transmissible hypovirulence is an epidemic disease of Endothia parasitica which reduces the pathogenicity of the affected pathogen but not its vitality. The hypovirulence is controlled by a genetic factor in the cytoplasm of the fungus. It has recently been shown that a ds‐RNA (virus‐RNA) is involved. In other cases, virus‐like particles have been found in hypovirulent strains. The effects of hypovirulence can be demonstrated both in vitro and in vivo . Transmission can occur between Endothia ‐strains within the same vegetative compatibility group. Hypovirulence occurs frequently in chestnut stands in southern Switzerland. To date, more than five different compatibility groups have been differentiated.