<![CDATA[Background: Fusarium stalk rot caused by Fusarium spp. remains a major threat to maize production. Although Bacillus spp. are effective biological control agents, their widespread application is hindered by the high cost of synthetic propagation media. However, whether inexpensive plant-based media can simultaneously support efficient bacterial propagation and preserve biocontrol efficacy against Fusarium stalk rot remains unclear. This study aimed to evaluate the potential of Bacillus sp. BTH-22 propagated in several alternative liquid media for controlling Fusarium stalk rot in maize. Methodology: The study was conducted through both in vitro and in vivo experiments in screen house using rice washing water, mung bean broth, and cowpea broth as alternative propagation media. Parameters observed included bacterial population density, antagonistic activity against Fusarium sp., disease incubation period, and disease intensity. Findings: The results demonstrated that all alternative media supported the growth of Bacillus sp. Bth-22, with cowpea broth producing the highest bacterial population density (2.85 × 10¹⁰ CFU mL⁻¹). In vitro antagonism assays revealed that Bacillus sp. BTH-22 effectively inhibited the growth of Fusarium sp., with the highest inhibition observed in cowpea broth medium (0.521%). In vivo application significantly delayed symptom development and reduced disease intensity in maize plants. The lowest disease intensity was recorded in the mung bean broth treatment (0.12%), compared with the control treatment (0.75%). Contribution: These findings indicate that alternative liquid media, particularly cowpea and mung bean broth, can serve as cost-effective and sustainable media for propagating Bacillus sp. BTH-22 as a biological control agent against fusarium stalk rot in maize.]]>
