Regional Institute of Wine and Oil

Sicily Peronospora 2018

The field situation is heterogeneous, characterized by extremes that are still good (Eastern Sicily, Etna) or acceptable under opposite conditions in which, due to the disease, production is compromised at 30 % and even beyond in limited areas (inner hills area and Sicily western centre). The worst contexts are obviously linked to the frequency of rainfall (average rainfall in June around 62 mm compared to an average of 12 mm recorded in the period 1981-2010), to varietal sensitivity (Grillo, Nero d'Avola, Inzolia, Chardonnay, Malvasia Bianca), but at the same time to defense lines that are not always adequate.

To date, in general, there are sporulating spots on new vegetation and browned grapes (larvate downy mildew). The risk of the proliferation of the fungus and a parallel worsening of the condition of the bunches remains. For now, unfortunately, it is still necessary to keep the vineyard protected, without extending the intervention shifts, renewing the protection and opting, in situations with active infections, more high-performance formulations with specific action.

Larval downy mildew When the infection occurs on bunches whose berries are already swollen or already darkened, no mold appears; these undergo strong dehydration, darkening and drying out.

The map of rainfall anomalies (cumulative for the months of March-May 2018) gives a good idea of where the greatest damage due to downy mildew infections is present; As is known, at our latitude, temperature does not play a limiting role in the development and spread of infections of the Plasmopara viticola fungus.

The graph and cartography are taken from the Sicily Region website www.observatorioacque.it

Dr. Felice Capraro