Chemical and biological control of artichoke crown rot caused by Sclerotium rolfsii [Cynara scolymus L.]

Inglés. Four pot trials were carried out in a controlled environment to test the effectiveness of different antagonists, compared with various chemical active ingredients, against Sclerotium rolfsii crown rot in artichoke. Rhizosphere competence antagonists, Trichoderma harzianum (T22 strain) and Streptomyces griseoviridis contained in commercial products, had very little effect on a disease in which roots were attacked only at the late stage. On the contrary, very good results were obtained with the Sardinian strain of Trichoderma viride (PVS 29T), when it was added to soil with a bran-perlite mixture. It was less effective when used in ovoli coat dressing. Similarly, hymexazol, added to soil, was also very successful in trial conditions, particularly when used with sclerotia produced in an artificial culture medium. On the other hand, poor results were obtained with tolclofos methyl when used for dressing ovoli. However, this practice could partly control only the infections already present inside the ovoli, but could do very little to control infections by sclerotia in soil. In short, progress in controlling S. rolfsii can be achieved by using control means which directly attack dormant or germinating sclerotia; among these, T. viride (PVS 29T) appears to be very promising

Italiano. Allo scopo di contrastare gli attacchi di Sclerotium rolfsii, agente del marciume del colletto del carciofo, sono state allestite prove in vaso per saggiare l´attività antagonistica di diversi microrganismi a confronto con alcuni principi attivi. Gli antagonisti colonizzatori della rizosfera, Trichoderma harzianum (isolato T22) e Streptomyces griseoviridis contenuti in formulati commerciali, si sono dimostrati poco efficaci. Al contrario, sono stati ottenuti risultati ottimi con l´isolato sardo di Trichoderma viride (PVS 29T), quando somministrato al terreno con una miscela di crusca e perlite. Parimenti efficace, nelle condizioni delle prove, è stato l´hymexazol, utilizzato in trattamenti al terreno. Invece, il tolclofos metile impiegato come conciante ha dato risultati scadenti. In definitiva, un progresso nella lotta contro S. rolfsii può essere raggiunto con mezzi che attaccano direttamente gli sclerozi quiescenti o germinanti; tra questi T. viride (PVS 29T) sembra molto promettente