Effects of Highly Diluted and Mineral Treatments on the Nutraceutical Properties and Phytopathological Status of Cauliflower

Dark leaf spot caused by Alternaria brassicicola (Schw.) Wilts. is a very common disease of Brassica crops world-wide. It often results in yield losses and reduced seed quality. This disease appears as small dark spots at all growth stages of the plant. In organic agriculture the control of dark leaf spot, as well as of most fungal diseases, is based on the use of mineral products such copper, that has a high efficacy and a long-lasting action. Unfortunately, copper use presents some disadvantages: it can be phytotoxic and it can accumulate in the ground with negative consequences on microflora and microfauna. For these reasons, European Union delivered a directive (Commission Regulation EC no. 473/2002) that imposes the reduction of copper use in organic agriculture. In this context, highly diluted preparations could represent suitable treatments, complementary or alternative to copper, in organic agricultural protocols. The literature on the effects of highly diluted treatments on plants provides a limited number of papers: besides germination and growth tests on different plant species, some experiments have been performed on phytopathological models, whereas very few and outdated descriptions are available as far as field trials are concerned . The aim of this work is to give a contribution on the effects of highly diluted treatments on dark leaf spot caused by A. brassicicola on cauliflower.