EVALUATION OF THE EFFECTIVENESS OF NATURAL ALTERNATIVE COPPER PRODUCTS AND LOW RATE COPPER FORMULATIONS AGAINST GRAPE DOWNY MILDEW IN ORGANIC VITICULTURE

Summary

The control of pathogenic fungi, especially downy mildew, represents the main problem in organic viticulture as only few fungicides, above all copper salts, can be used. As the copper causes problems of environmental impact, the Regulation EC n. 473/2002 fixed a ceiling on the use of copper compounds. Two years field trials were carried out in organic vineyeards to test the effectiveness, against Plasmopara viticola (Berk. et Curt.) Berl. et De Toni, of alternative copper products and low rate copper formulations, able to take place or to reduce copper quantities used. Amoung the alternative substances, in the first year of activity we examinated phito-stimulant and cuprics, while in the second year we examinated natural extracts, both vegetables and animals, and natural compound associates to the copper. The achieved results have underlined that, using the low rate copper formulations examinated, the total copper quantities were always less than 6 Kg copper per hectare, in accordance with the provisions of Regulation EC. The alternative products investigated have not guaranteed, instead, an adequate protection with high pressure od downy mildew. The trials confirm that the copper is indispensable for plant protection in organic farming, as it is not possible to replace it. We can only reduce the copper quantities used, at this point of time, but further studies are necessary to find appropriate alternative solutions able to control pathogenic agents in organic farming.