Antagonistic Test of Several Bacterial Isolates Against Fusarium Sp. Causing Fusarium Wilt in Purple Eggplant (Solanum Melongena L.)

Fusarium sp. is one of the pathogens that causes fusarium wilt disease in purple eggplant (Solanum melongena L.). The control measures commonly used to date involve the application of chemical fungicides, which have negative impacts on the environment and health. Therefore, alternative control measures using safe and environmentally friendly antagonistic bacteria are needed. This study aims to determine the ability of Lactobacillus bulgaricus, Lactobacillus plantarum, Paenibacillus polymyxa, and Pseudomonas fluorescens to inhibit the growth of Fusarium sp. fungi and to identify the antifungal compounds produced by these four bacteria. Fusarium sp. was isolated from purple eggplant plants exhibiting fusarium wilt symptoms. The fungal isolates were purified and identified macroscopically and microscopically. Antagonism tests were conducted in vitro using the disk diffusion method, while the identification of active compounds was performed using Gas Chromatography-Mass Spectrometry (GC-MS). The results of the disc diffusion assay showed that L. bulgaricus exhibited the highest inhibition zone of 4.50 mm, followed by L. plantarum with 4.00 mm. In contrast, P. polymyxa and P. fluorescens showed no inhibitory activity 0 mm. GC-MS analysis showed that the filtrates of the four bacteria contained active antifungal compounds, namely cinnamaldehyde (2-propenal, 3-phenyl), hexadecanoic acid methyl ester, 2-benzenedicarboxylic acid bis(2-ethylhexyl), 8-octadecenoic acid methyl ester, and methyl tetradecanoate.