BIOCONTROL OF PRE- AND POST-HARVEST BUNCH DECAY OF WINE AND TABLE GRAPES
S DROBY1, T ZAHAVI1, L SCHENA2, L COHEN1, B WIESS1, A DAUS1, R BEN-ARIE1, E CHALUTZ1 and A IPPOLITO2
1Dept. Postharvest Science, ARO, The Volcani Center, PO Box 6, Bet Dagan 50250, Israel; 2Dip. Di Protezione Delle Piante Dalle Malattie, Universita Degli Studi Di Bari, Via Amendola, 165/a, 70126 Bari, Italy
Background and objectives
Development of economically and environmentally sound control strategies of bunch decay using biocontrol agents is being pursued by several laboratories around the world. For the past 4 years we have been isolating and developing indigenous antagonistic yeasts effective against pathogens of grape bunch.
Results and discussion
Efficacy of yeast isolates was also evaluated in large scale tests in the vineyard for the control of pre- and post-harvest decay of wine and table grapes. The antagonists were applied in the vineyard in weekly intervals starting the fourth week before harvest. Results of two field tests conducted in two successive years showed 50-70% reduction of incidence of Botrvtis and Aspergillus decay developed in the vineyard. In table grapes, the reduction in incidence of post-harvest Botrytis rot ranged from 30-50%. A population study performed to evaluate the survival of the yeast antagonists under field conditions indicated a successful colonization of grape-berry surface by the yeast antagonists. In addition, a synergistic effect was found between the antagonists and low doses of two fungicides commonly used for the control of bunch rot. This may facilitate the development of an IPM approach based on either the combination of yeast antagonists and low doses of fungicides, or an alternation control program aimed at reducing the number of fungicide sprays.