ABSTRACT Maize ( Zea mays L.) is a globally important crop used for food, feed and industrial raw materials. However, fungal diseases, particularly southern corn leaf blight caused by Bipolaris maydis , lead to severe yield losses. As an alternative to fungicide treatments, this study aimed to identify bacterial isolates and their crude extracts with antagonistic potential against B. maydis and efficient suppression of southern corn leaf blight. The research comprised four experimental stages: (E1) dual‐culture assays to select six antagonistic bacterial isolates; (E2) production of cell‐free crude extracts to determine their antifungal properties; (E3) in vitro evaluation of the compatibility and combined effect of bacterial cells and crude extracts; and (E4) greenhouse experiments using the ‘Potiguar’ maize cultivar to assess disease severity reduction in vivo. In greenhouse trials, bacterial suspensions or crude extracts were sprayed on the foliage to run‐off, simultaneously with B. maydis inoculation, followed by high‐humidity incubation. Six isolates— Bacillus velezensis , B. altitudinis , Pseudomonas putida , P. aeruginosa , Priestia megaterium and a Pantoea sp. reduced the pathogen's colony area by at least 50% after 7 days of co‐culture. Their crude extracts resulted in antibiosis, reducing colony area by 11.0% to 77.7%, while Pantoea sp. suppressed leaf blight severity by 28.2% in greenhouse conditions, and P. aeruagina 'crude extract by 45.3%. These results contribute to developing sustainable alternatives for southern corn leaf blight management.
Franco et al. (2026) studied this question.