Natural products alone or with copper vs. grape downy mildew: efficacy, costs, Cu impact.

In organic farming copper is one of the few fungicides that can be used and the only effective against downy mildew. Due to the problems of environmental impact associated with the use of this heavy metal, the European Union decided to restrict its use (Annex II Regulation EC n. 889/2008). In order to assess the possibility of replacing the copper or reduce the quantities used, we tested natural products and low rate copper formulations in field trials. The anti-downy mildew activity of these formulations has been studied in an organic vineyard. During the two years of activity we also estimated the economic cost of use of the products to assess their possible use in agricultural practice.