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.

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It is shown the efficiency of the application of preparative forms (dry and liquid) of Kartofin during the growing season 2016-2018 years against major diseases of potatoes and the impact on the growth and development of culture. Biopreparation possesses high fungistatic effect, protecting potato plants against rhizoctonia disease, potato blight and late blight under field conditions and tubers of the new crop from dry rot. In years of low and moderate disease development, the effectiveness of the studied Potato biopreparation on the Sante variety was at the level of the reference chemical variant, equally reducing the distribution and degree of disease development. In the years of epiphytotic disease development fungistatic effect of the biopreparation was inferior in efficiency to chemical fungicides, but had a significant protective effect compared to the control, reducing the distribution of rhizoctonia disease by 22.5%, potato blightby 20.7%, late blight by 12.8% on average. The results of tuberous analyses after harvesting showed a decrease in the percentage of tuber damage by dry rot in variants with Kartofin (1.7 and 1.4%). The yield of the standard potatoes after application of Kartofin was slightly higher than in the control – by  5.1–7.7%.

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In field experiments, five schemes of using drugs of different spectra of action were tested in order to reduce the chemical load on the potato biocenosis. Insufficient efficiency of using only biologicals in protecting potatoes from diseases is quite natural. Its use should be combined with chemical pesticides, reducing the number of chemical treatments, but not reducing the effectiveness in combating diseases and crop yields. The study of the effect of the biological product Kartofin as a disinfectant of potato tubers and a fungicide for the treatment of vegetative plants in comparison with the chemical preparations Emesto Quantum and Consento, the alternation of the biological product and chemical fungicides on the economic indicators of the Sante variety. According to the results of twoyear testing it was revealed that the biological product Kartofin and chemical preparations do not cause negative effect on the growth qualities of potatoes and on its immunity. The use of the biological product contributed to a decrease in the development and spread of rhizoctoniosis and alternaria, while being inferior in effectiveness to chemical drugs. Against the causative agent of late blight, the use of the biological product Kartofin was ineffective. At the same time, replacing one treatment with Kartofin during the period of closing the tops in rows for the Consento treatment enabled to reduce the degree of development of the disease by 2 times until the middle of the growing season. The use of the chemical fungicide Consento enabled to protect plants from late blight by the end of the growing season with an efficiency of up to 54.2%. The use of the biological product Kartofin during the growing season enabled to increase the yield by 6.8-7.9% (1.2-1.4 t / ha) compared to the control. The replacement of one treatment with Potato for the Consento treatment increased the yield by 14.1-16.9% (2.5-2.9 t / ha). The use of the chemical dressing agent Emesto Quantum followed by the processing of Consento plants increased the yield by 18.9% (3.3 t / ha). The treatment of seed tubers with Potato helped to obtain a crop free from rhizoctonia. Thus, the use of Kartofin as a disinfectant and fungicide for treatments during the growing season with the replacement of one treatment with Consento during the closing of the tops in a row increases the yield of standard products by 20.1%.