ISHS Acta Horticulturae 513: XXV International Horticultural Congress, Part 3: Culture Techniques with Special Emphasis on Environmental Implications, Disease, Pest Control and Integrated Pest Strategies
SOIL-BORNE PHYTOPATHOGENIC FUNGI CONTROL BY CLEOME HASSLERIANA GREEN MANURE |
| Authors: | L. Lazzeri, L.M. Manici, O. Leoni, S. Palmieri |
| Keywords: | Cleome hassleriana, Pythium spp., glucocapparin, glucosinolates, methyl-isothiocyanate, soil-borne pathogens |
| Abstract:
Recent studies report the suppressive activity of Brassica plant green manure against soil-borne phytopathogenic fungi as an ecological alternative to methyl-bromide in horticulture. This fungitoxic activity is due to the presence in all plant tissues of the glucosinolate (GL)-myrosinase system which, in presence of cellular damage, produces isothiocyanates and/or nitriles. These compounds present a strong bio-activity which depends on their chemical structure. The above ground biomass of Cleome hassleriana, of the Cleomaceae family, contains a large quantity of glucocapparin (methyl-glucosinolate) and glucocleomin (2-hydroxy-2-methylbutyl-glucosinolate). This composition is interesting because one of the hydrolysis products of glucocapparin is methyl-isothiocyanate, which is a biocidal ingredient of some commercial fumigants. Two years of full field Cleome cultivation in Northern Italy demonstrated that at the flowering stage, a selection named ISCI2 can produce more than 3.5 t/ha of dry matter with more than 25 kg/ha of glucosinolates. To demonstrate the fungitoxic activity of C. hassleriana green manure some experiments were carried out in pots under controlled conditions. Fresh C. hassleriana tissues collected at flowering stage were ground and mixed with natural Pythium spp. infested soil. Total fungi strongly increased in all fresh tissue treatments. On the contrary, a treatment with a common green manure crop increased Pythium propagules four-fold while after three weeks C. hassleriana treatment reduced Pythium by 88% as compared to untreated soil. These results suggest further studies to verify the potential use of C. hassleriana as an efficient tool to control some soil-borne pathogens in horticulture. | |
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