Identification of antagonistic bacteria against peanut stem rot disease (Sclerotium rolfsii Sacc.) on the peatland of Kuala Pesisir-Nagan Raya, Indonesia

Peanut cultivation in peatlands has major obstacles in terms of controlling plant diseases. This research aimed to identify and characterize bacteria which have the potential as biological control agents against S. rolfsii in the peatlands of Kuala Pesisir Nagan Raya. This research was conducted in the Kuala Pesisir sub-district, Nagan Raya District, Aceh, Indonesia. The research activities include isolation, morphological identification, pathogenicity testing, antagonistic testing, and molecular identification. After the first screening, 25 bacterial isolates were to be observed further. At the root of the peanut plants the colonies were mostly bacillus, some of them were coccus. In gram staining, there were many gram-negative isolates compared to gram positive. Non-pathogenic bacterial isolates have good growth potential (85% - 100%), except for B3 bacterial isolates (74%). The peanut seeds in non-pathogenic bacteria that have good germination were in the range of 80% - 96% of the germination capacity. Peatland bacteria that interact with type D have the potential to act as antagonistic agents against S. rolfsii. There are bacteria which were promising to act as an antagonistic agent against Sclerotium rolfsii in the research area. Based on morphological and DNA characteristics, the bacteria were identified as Bacillus sp.