Colletotrichum coccodes in potato and tomato leaves in Russia

Colletotrichum coccodes is a plant pathogenic fungus affecting different organs of potato, tomato, and some other plants. The leaf infection with C. coccodes may result in a rapid development of infection nidus and high losses caused by the infection of tomato fruits and potato tubers during harvesting. Our study showed the presence of C. coccodes on tomato and potato leaves with dry necrotic lesions. The presence of a DNA region specific for C. coccodes was detected in DNA samples isolated from infected tomato leaves collected in the Rostov region (7 and 1 samples from two distinct fields) and the Krasnodar Territory (5 samples from one field). In the case of potato leaf samples, the frequency of C. coccodes detection was lower than in tomato leaves. This fungus was revealed only in five potato leaf samples: one from the Northern Ossetia, one from the Kostroma region, and three from the Mariy El Republic. Pure cultures of two isolates were isolated from a naturally infected potato leaf. According to morphological criteria, size of spores and sclerotia, habitus of colonies, and species-specific DNA sequences, both strains completely corresponded to C. coccodes.