Abstract Book: FEMS MICRO Milan 2025: Congress & Exhibition, 14-17 July, Milan, Italy Bacillus mycoides as a potential biocontrol agent for Fusarium suppression 2025 info:eu-repo/semantics/conferenceProceedings https://unilib.phaidrabg.rs/o:8145 application/pdf 2365012 bytes Jevđenović, Galina Knežević, Magdalena Maksimović, Jelena Jovković, Marina Dervišević, Marina Buntić, Aneta eng All rights reserved Abstract: Introduction: Suppression of fungal pathogens that are responsible for massive crop losses, with Fusarium species as the most prevalent ones, represents a huge challenge in sustainable agriculture. Application of bacterial inoculants is an effective alternative to chemicals as it poses no health risks and has an insignificant impact on the environment. Objective: The application of new bacterial strain Bacillus mycoides BHC 3.2 for suppression of Fusarium poae, Fusarium graminearum, Fusarium proliferatum and Fusarium oxysporum was the objective of this research. Method: Antifungal activity of isolates was tested in vitro on PDA medium using dual culture method and inhibition of fungal growth was calculated based on the formula: Inhibition(%)=[(Fungal control (mm) - Treatment (mm))/Fungal control (mm)] x 100. Production of siderophores and indole-3-acetic acid (IAA) was determined by growing strain on Chrome Azurol S (CAS) Blue agar and in tryptophan (2 mg/mL) enriched nutrient broth (NB) by using Salkowski reagent, respectively. Findings: Among tested fungal pathogens, strain BHC 3.2 showed the strongest antagonistic effect against F. poae with inhibition over 45%. BHC 3.2 also showed antagonistic effect against F. graminearum, F. proliferatum and F. oxysporum with inhibition lower than 35%. The production of siderophores was not recorded for BHC3.2, while the production of IAA was 3.69 μg/mL. Conclusion: Previous studies showed that B. mycoides could be used for reducing the severity of Fusarium infections in crops. Results of this research highlight the feasibility of utilizing Bacillus mycoides BHC 3.2 in formulating biofertilizers, thereby offering environmentally friendly strategy for plant pathogens control.