Potential of Bacillus sp. KITA and Bacillus sphaericus OP6 as Effective Biocontrol Agents against Fusarium sp. in Jatropha curcas in Mali

Backgroud and Aims: Jatropha curcas L., a species native to Mexico, has recently been recognised as a promising source of biofuel. This study aimed to evaluate the biocontrol potential of two Bacillus species, Kita and OP6, against Fusarium, a major pathogen affecting Jatropha curcas in Mali. Study Design: Randomized complete block design with six treatments: Fusarium (F); Bacillus sp Kita (K); Bacillus sp.OP6 (OP6); K + F; OP6 + F: Control (C) and three replications. Place and Duration of Study: The study was conducted in the greenhouse research area of the LaboREM-Biotech at the Faculty of Sciences and Techniques at the USTTB in Mali. Methodology: Fusarium sp. was isolated from diseased Jatropha curcas leaves and identified morphologically. Bacillus strains were tested in vitro for antagonistic activity and in vivo for promoting plant growth. The treatments included Fusarium alone, Bacillus strains alone, combinations of Bacillus strains, and a control treatment. Growth parameters were measured and analysed using SAS software. Results: Bacillus sp. Kita and OP6 strains exhibited significant (>70%) inhibition of Fusarium growth in vitro. In vivo, co-inoculation with Bacillus strains improved seed germination, leaf number, plant height and biomass, compared with Fusarium-only and control treatments. Statistical analysis confirmed significant differences (P < 0.05) between the treatments. Conclusion: The Bacillus species Kita and OP6 exhibit strong biocontrol and plant growth-promoting properties. This makes them a sustainable alternative to chemical pesticides for managing Fusarium in Jatropha cultivation.