Formulation-dependent efficacy of Bacillus velezensis BEIB-46 for the biological control of Meloidogyne incognita in cotton

Abstract

Meloidogyne incognita is one of the main phytonematodes affecting cotton productivity, requiring sustainable control alternatives to chemical nematicides. This study evaluated the efficacy of different bioinputs based on Bacillus velezensis BEIB-46 for the biological control of M. incognita and their effects on cotton development. The strain was identified through high-resolution genomic analyses, followed by production via submerged fermentation and formulation into four distinct forms: fermented broth (6 × 10⁸ CFU/mL), fermented broth supplemented with 10% composting extract (4 × 10⁸ CFU/mL), concentrated wet biomass of B. velezensis BEIB-46 (1 × 10 1 ⁰ CFU/g), and concentrated dry biomass of B. velezensis BEIB-46 (1 × 10 1 ⁰ CFU/g), applied at different doses at planting. After 98 days, the final nematode population, reproduction factor, control efficiency, and agronomic parameters were evaluated. All B. velezensis treatments significantly reduced the M. incognita population compared with the untreated control. The highest control efficiencies were observed for the concentrated formulations, particularly the dry solid form, which achieved up to 83.4% efficiency and reproduction factors of 0.4 and 0.3. In addition to nematode suppression, the treatments significantly increased fresh root mass and shoot dry mass, indicating a biostimulant effect. The concentrated dry formulations (2 and 5 g/ha) demonstrated superior performance by combining high nematicidal efficiency with root or shoot growth promotion, as well as improved commercial attributes and operational feasibility, highlighting the potential of B. velezensis BEIB-46 as a sustainable alternative for the management of M. incognita in cotton cultivation.