engleski

Natural biological control of chestnut blight in Croatia

The chestnut blight fungus Cryphonectria parasitica has been responsible for the decline of chestnut trees in Croatia for five decades. In order to investigate whether virus-induced hypovirulence is naturally present in all C. parasitica populations or human-mediated biological control is necessary, we sampled 338 fungal isolates from 10 chestnut populations throughout chestnut-growing coastal and continental areas of Croatia. Altogether, 18 vegetative compatibility (vc) types were identified. Perithecia and both mating types of C. parasitica in approximately 1:1 ratio were found in all populations suggesting sexual reproduction of the fungus. Although quite high vc type diversity and sexual reproduction were confirmed, which usually presents an obstacle for the spreading of the hypovirus, natural hypovirulence was evident in all populations. Incidence of hypovirus-infected isolates ranged from 12.7% in coastal to 66.6% in the continental part of the country. All viral isolates belonged to the Italian subtype of Cryphonectria hypovirus 1 (CHV-1) and were closely related to the isolates found in other European countries.

Cryphonectria parasitica; Castanea sativa; Cryphonectria hypovirus 1; biological control; chesnut blight

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