Endophytic bacterial consortia as biocontrol of purple blotch and plant growth promoters of shallots

Abstract

Endophytic bacteria have been reported to have roles as biocontrol agents and plant growth promoters. The application of endophytic bacteria in the form of mixed culture [consortia] will provide better effectiveness than when applied alone. This study aimed to obtain a consortium of endophytic bacteria that is effective as a biological control for purple blotch [Alternariaporri], promote the growth and yield of shallots. The research was arranged in a completely randomized design [CRD] consisting of 7 treatments with three replications. The consortium used was a mixture of two strains of Bacillus sp., two strains of B. cereus, two strains of Serratia marcescens, Bacillus subtilis, Azotobacter, Azospirillum, and P. fluorescens. The variables observed in this study included disease progression [incubation period, disease incidence, and disease severity], plant growth [number of leaves and plant height], and yield [fresh weight and dry weight of bulbs]. The results showed that the C consortium [Bacillus sp. strain SJI, Bacillus sp. strain HI, Serratia marcescens strain ULG1E4 and Serratia marcescens strain JBIE3] and G consortium [Bacillus sp. strain SJI, Bacillus sp. strain HI, Bacillus subtilis, Pseudomonas fluorescens, Serratia marcescens strain ULG1E4 and Serratiamarcescens strain JBIE3] were the best consortia in suppressing purple blotch disease, as well as in improving the growth and yield of shallots.