Assessment of Conjugate Complexes of Chitosan and Urtica dioica or Equisetum arvense Extracts for the Control of Grapevine Trunk Pathogens

In the work presented herein, we analyze efficacy of three basic substances that comply with European Regulation (EC) No 1107/2009, namely chitosan, horsetail (Equisetum arvense L.) and nettle (Urtica dioica L.), for control grapevine trunk diseases (GTDs) in organic farming. The E. U. aqueous extracts, prepared according to SANCO/12386/2013 SANTE/11809/2016, have been studied by gas chromatography–mass spectrometry (GC-MS), identifying their main active constituents. substances, either alone or combination (forming conjugate complexes), tested vitro against eight Botryosphaeriaceae species, vivo, grafted plants artificially inoculated Neofusicoccum parvum Diplodia seriata. A clear synergistic behavior between chitosan two plant extracts has observed mycelial growth inhibition tests (resulting EC90 values as low 208 μg·mL−1 some isolates), statistically significant differences found terms vascular necroses lengths treated non-treated plants, providing further evidence aforementioned synergism case D. reported data supports possibility extending applications these Viticulture beyond treatment mildew.