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Colletotrichum species are the causal agents of potato and tomato diseases, such as black dot and anthracnose. Several new species and species complexes were recently established. Thereby, a reassessment of the genus diversity is required. The study revealed two species, Colletotrichum coccodes and Colletotrichum nigrum, as Russia's main disease agents of cultivated Solanaceae plants. Black dot and anthracnose in potato were caused exclusively by C. coccodes, whereas the same diseases in tomato, eggplant, and pepper were predominately caused by C. nigrum. However, one isolate of C. coccodes was also identified as an agent of the tomato disease. Five potentially hybrid isolates were discovered. Morphological examination and pathogenicity assessment revealed no significant differences between the two Colletotrichum species. All isolates were sensitive to the fungicides azoxystrobin, difenoconazole, and thiabendazole, which are currently used in agriculture. This is the first report of the occurrence of C. nigrum in Russia. [ABSTRACT FROM AUTHOR]

Early blight (EB) is a destructive disease affecting potato and tomato plants in Russia, caused by a heterogeneous group of plant pathogenic Alternaria fungi. The current species delimitation in Alternaria sect. Porri with medium to large conidia and a long (filamentous) beak is based on molecular data. In this study, the ITS, GAPDH, RPB2, TEF1, and Alt a 1 gene regions were analyzed in 41 large-spored Alternaria isolates obtained from diseased potato and tomato plants collected from 13 regions in Russia. Our data revealed five pathogenic species (A. alternariacida, A. grandis, A. linariae, A. protenta, and A. solani). Two species (A. solani and A. linariae) were found to be associated with early blight of tomato. Alternaria linariae and A. protenta were confirmed as the major causal agents of tomato and potato early blight, respectively. There were no phylogenetic groupings among tested Russian Alternaria isolates associated with their locality. [ABSTRACT FROM AUTHOR]