FUNGI ASSOCIATED WITH ESCA DECLINE AND THEIR IN VITRO CONTROL BY CHITOSAN

Esca is a devastating and insidious disease that affects vineyards in major grape-producing areas worldwide. Several esca characteristics make the effectiveness of control strategies still difficult (types of microorganisms involved, correlation of foliar symptoms with wood deterioration). The aims of our research were to identify fungal pathogens associated with esca decline and to evaluate their in vitro control by chitosan. Research was carried out in Bucharest (N 44 degrees 25', E 26 degrees 6') in 2009, in a plantation founded in 1994 of Feteasca regala cultivar grafted on Kobber 5 BB. The type of vine training system can be a favourable factor for esca decline. Both, the mild and the severe form of esca were observed. Samples obtained from vines with characteristic esca symptoms were examined for the presence of pathogenic fungi. The fungi isolated from the wood were included in the genera: Phaeoacremonium, Phaeomoniella, Phomopsis, Fomitiporia, Fusarium, Alternaria, Cladosporium, Aspergillus and Botryosphaeria. In vitro assays investigated the influence of chitosan on the mycelial growth of esca pathogens. The effective concentrations which inhibit mycelia growth by 90% were calculated. Our results highlighted the potential of chitosan to control esca pathogens. Further investigation is needed to set an integrated management program in which chitosan could be used as wound dressing.