Prospective for biocontrol implementation of the chestnut blight fungus Cryphonectria parasitica in Friuli Venezia Giulia

Abstract: The fungus Cryphonectria parasitica, the causal agent of chestnut blight, gives rise
to important economic losses worldwide. The disease can be efficiently managed through the
Cryphonectria-Hypovirus pathosystem. Indeed, hypoviruses, specifically Cryphonectria
hypovirus 1 (CHV-1), which is mainly transmitted through hyphal anastomosis among vegetative compatible (VC) C. parasitica types, can reduce the virulence and pathogenicity of the fungus. However, the recrudescence of the disease in Friuli Venezia Giulia required a new study of the C. parasitica population to evaluate the implementation of biocontrol strategy in the region. Therefore, isolates of C. parasitica were characterized both by the analysis VC-types and mating-type idiomorphs. In addition, the presence and occurrence of CHV-1 was studied and by the susceptibility of commercial and local chestnut cultivars to the disease was evaluated in an in vitro experiment. The data obtained pointed out a high genetic variability of the fungus and a low occurrence of hypovirulent strains, revealing a challenging prospective to find a successful biocontrol solution.