|Abstract in English:|
Corky root is an important soilborne disease of tomato caused by Pyrenochaeta lycopersici. Effect of compost, obtained from organic fraction of municipal solid wastes, on the reduction of corky root damages on canned tomato, was evaluated in a field naturally infested with the fungus in southern Italy. At harvesting, disease severity, measured on roots collected from plots treated with 15 (C15) and 45 (C45) t ha-1 of dry compost, was significantly lower than that measured on roots collected from mineral fertilized (MIN) or untreated (CNT) plots. Detection, by PCR, performed on symptomatic root fragments, confirmed P. lycopersici as the causal agent. The number of potentially antagonistic spore-forming bacteria, supplied with compost was evaluated on soil samples collected during tomato growth. Mean values of these bacteria, expressed as CFU g-1 of soil, were 3.4×105 for C15, 1.4×106 for C45 and 1.5×105 for MIN; mean values in the soil not treated with compost and chemical fertilizers was 9.6×104. The lowest value of spore-forming bacteria in the soil samples not treated with compost and the higher number of these bacteria in the compost (3.58±1.09×106 CFU g-1 of dry weight) and in the soil samples manured with compost, seems to indicate a direct role of these bacteria in the control of P. lycopersici. An higher number of these spore-forming bacteria were tested in vitro for antibiosis activity against P. lycopersici. The major part of them showed antibiosis activity against this soil-borne pathogen.