Abstract
<title>Abstract</title> <p> The agroecosystems are affected by phytopathogens such as <italic>Fusarium sp</italic> . Nevertheless, rhizobacteria isolated from different crops have demonstrated effective biocontrol against various phytopathogens. The <italic>in vitro</italic> biocontrol effect of rhizobacteria isolated from arugula ( <italic>Eruca vesicaria</italic> ) in an aquaponic system against <italic>Fusarium sp</italic> . was evaluated. Thirty rhizobacteria were isolated from the rhizosphere and characterized phenotypically and biochemically. Most isolates were Gram-positive bacilli, showing variable enzymatic activity, motility, and low sulfate and indole reduction capacity. Antagonism tests revealed four morphotypes that exceeded 50% inhibition of the phytopathogen. These were molecularly identified as <italic>Bacillus pumilus</italic> (61.29%), <italic>Bacillus cereus JCM</italic> (55.56%), <italic>Brucella pecoris</italic> (52.40%), and <italic>Bacillus cereus ATCC</italic> (50.00%). The results demonstrate a high diversity of rhizobacteria in aquaponic systems. Furthermore, four of these isolates exhibited significant biocontrol potential against the phytopathogen <italic>Fusarium sp</italic> . These findings suggest that aquaponic systems represent a promising source of beneficial microorganisms for biological control strategies. Further studies are required to evaluate their efficacy under <italic>in vivo</italic> conditions and to elucidate the mechanisms involved in pathogen suppression. In conclusion, the rhizobacteria isolated from <italic>E. vesicaria</italic> in aquaponics constitutes a valuable alternative for sustainable management of <italic>Fusarium</italic> diseases. </p>