dc.description.abstract | In orchid plants, bacteria that cause soft rot enter the plant tissue through wounds, causing soft rot to thrive in the plant tissue. Symptoms of soft rot in orchids are characterized by the appearance of blackish brown spots, leaves become runny and leaves become soft, turgor pressure on the leaves disappears, and produces a foul odor. Decay that occurs in young plant tissue quickly compared to adult plant tissue. The purpose of this study was to determine the antagonistic properties of endosymbiotic bacteria against soft rot bacteria tested on Phalaenopsis sp. The research method used was in vivo, namely the Phalaenopsis sp. orchid plant introduced with endosymbiotic bacteria then tested using soft rot bacteria. The results of this study were obtained on the soak + flush test treatment. | vi |