Abstract
Fruit production in central Europe takes place in permanent cropping systems and is affected by replant disorders, although soil organic matter content does not represent a fertility limiting factor in those growing areas. The consequent crop yield decline is mainly due to biotic causes, even if it is mediated by plant vigour. Therefore, the most appropriate strategy for controlling replant disease in organic cropping systems of central Europe is to exploit biological soil resources. To prove feasibility of this strategy, functionality of two populations of endophytic fungi isolated in apple orchards was evaluated. Antibiosis and potentiality of plant growth promotion, as observed in Fusarium oxysporum, as well as antagonism toward the pathogen Cylindrocarpon in apple tree root colonization, as observed in binucleate Rhizoctonia, indicate the possibility to reduce root pathogens and to increase plant growth in renewed apple orchards by exploiting microorganisms naturally present in soil.