Study of B. subtilis and Tr. harzianum strains interaction and pathogenic microorganisms of zucchini diseases

The purpose of the study is to identify effective types and forms of application of antagonist microorganisms to prevent the development of characteristic diseases that cause spoilage of zucchini, for their further use in the development of biological control technologies. Tasks: to study the composition of the phyllosphere and phytopathogenic microorganisms on it, causing diseases of zucchini; to establish the properties of antagonist microorganisms of B. subtilis strain IPM 215, B. subtilis strain M-22 VIZR, Trichoderma harzianum strain G 30 VIZR in relation to the causative agents of characteristic bacterial and fungal diseases of zucchini - Alternaria radicina, Fusarium culmorum and Pectobacterium carotovora. The objects of the study are zucchini Marsella F1, CA7585, Dasha F1, Nevira F1, Yasna F1, Donya Perfecta F1, grown in 2022 in the Krasnodar Region (Temryuksky District, IP Erokhin); antagonist microorganisms B. subtilis strain IPM 215, B. subtilis strain M-22 VIZR, Trichoderma harzianum strain G 30 VIZR; the mold fungi Alternaria radicina and Fusarium culmorum and the bacterium Pectobacterium carotovora. It has been established that the treatment with culture fluid (CL) of B. subtilis strain IPM 215 of forcibly infected squash discs reduces the damage by an average of 15-35 % compared with control samples; treatment of QOL with B. subtilis strain M-22 VIZR by 25-65 %; treatment of QOL Trichoderma harzianum strain G 30 VIZR - by 65-80 %. It can be argued that the use of CL of mold cells Tr. harzianum strain G 30 VIZR is promising for further research on the storage of various vegetables.