RUOLO DEI TRATTAMENTI ESTINTIVI NEL CONTROLLO DEL MAL BIANCO DELLA VITE

ROLE OF SANITATION IN CONTROLLING GRAPEVINE POWDERY MILDEW Erysiphe necator, the causal agent of grapevine powdery mildew, overwinters, in many grapevine growing regions, as chasmothecia, which, in the following spring, discharge ascospores that cause primary infections and trigger powdery mildew epidemics. The disease is currently controlled with repeated applications of synthetic fungicides and sulphur during the grapevine growing season. The possibility to include sanitation treatments (against the overwintering primary inoculum) control strategies was evaluated. In vineyards with a high dose of primary inoculum different synthetic fungicides applied after harvest and a Biocontrol agent based on Ampelomyces quisqualis (AQ10) applied before and after harvest (i.e., during the formation and maturation of the chasmothecia), decreased disease severity on bunches until pea-sized berries stage in the following season, with an average efficacy of 59%. In the trials were sanitation treatments were coupled with early season treatments, synthetic fungicides, A quisqualis and a mineral oil (Polithiol) applied before bud burst, reduced disease severity on bunches by 98%; early season treatments with only sulphur showed an average efficacy of 80%. Sanitation treatments with AQ10 and/or mineral oil coupled with early season treatments with sulphur significantly increased the disease control efficacy of bunches, as compared to the sole use of sulphur.