Single and combined effects of Pythium oligandrum Po37 and a consortium of three rhizobacterial strains on Sclerotinia stem rot severity and tomato growth promotion

Individual plant growth-promoting rhizobacterial (PGPR) strains (Bacillus thuringiensis B2, Bacillus subtilis B10 and Enterobacter cloacae B16) their combination were used, with or without Pythium oligandrum, against Sclerotinia sclerotiorum. In vitro, all biological control agents (BCAs) reduced successfully hyphal growth of the targeted pathogenic fungus. They displayed antifungal activity by more than 50% compared to controls. planta trials conducted two years in row led a significant decrease stem rot severity months after antagonist’s application onto infected tomato plants. The reduction reached 75% using mixtures 72% P. oligandrum alone, potential three-strain consortium was also assessed. Increased height disease-free plants obtained (60%) (47%). BCA’s mixture increased treated inoculated S. sclerotiorum (up 80%) untreated fresh weight aerial parts roots 42 30% over following treatment rhizobacteria respectively. On both trials, highest growth-enhancing effect achieved combined based on (Po37 + B2 B16). rhizospheric microbial communities assessed Single Strand Conformational Polymorphism (SSCP). Differences genetic structure fungal bacterial observed treatments applied trials.