Effect of the nursery application of bioorganic fertilizer on spatial distribution of Fusarium oxysporum f. sp. niveum and its antagonistic bacterium in the rhizosphere of watermelon

► The BIO suppressed Fusarium wilt and promoted the growth of watermelon.► Rhizobox was employed to investigate the microbes' behavior in watermelon rhizosphere. ► Abundances of the pathogen and its antagonist were detected at different distance from the rhizoplane. ► The BIO can significantly decrease the number of the pathogen in the rhizosphere. ► The BIO can greatly increase the population of the antagonistic bacterium in the rhizosphere.