Fusarium fujikuroi and related species from rice plants affected byBakanae disease in Northern Italy

More than 150 strains of Fusarium species were isolated from stems and roots of the rice plants with bakanae disease symptoms collected in the last two years. Based on the morphological identification, the main species isolated resulted F. fujikuroi. Moreover, F. proliferatum and, at a lesser extent, F. subglutinans and F. oxysporum were also frequently isolated, while F. verticillioides and F. graminearum were rarely identified. These data showed that F. fujikuroi is a pathogen highly occurring in the rice cultivation in Italy. To this respect, Balmas et al. (2000) reported that F. fujikuroi was isolated from blighted and foot rotted rice seedlings in Sardinia, but no bakanae disease symptoms were observed. On the contrary, our data over two years showed that the occurrence of this disease could become endemic in the Northern Italy areas where rice cultivation is spread. The association of other species of Fusarium, mainly belonging to Liseola section, to F. fujikuroi in plants affected by bakanae disease was also reported by other authors in Nepal (Desjardins et al., 1997; Desjardins et al., 2000). In our report, F. proliferatum is a highly occurring species on rice plants and this is consistent also with the report of Balmas et al. (2000, l.c.). On the other hands the absence of F. nygamai and the occurrence of F. subglutinans was in contrast with the aforementioned Balmas et al. report. Finally, the assessed capability of F. fujikuroi to produce toxic metabolites such as fumonisins, moniliformin, beauvericin and gibberellins is worrisome. In addition, the other species isolated and, in particular, F. proliferatum also represent a risk for their toxigenic potentiality. Strains will be opportunely evaluated to confirm morphological identifications by using mating population concept and to check their potential toxigenic capacity. However, the isolation of such toxigenic species from rice plants affected by bakanae disease showed that a potential risk for the rice consumption does exist.