ISOLATION AND SELECTION OF ANTAGONISTIC Bacillus sp. AGAINST Ralstonia solanasearum CAUSING BACTERIAL WILT DISEASE IN CUCUMBER

Abstract

Bacterial wilt disease is one of the most damaging diseases of cucumber. The aim of this study is to determine strains that cause bacterial wilt disease in cucumber and to select some Bacillus that is capable of antagonism to Ralstonia solanacearum, causing the wilt disease in cucumber. The result showed that the strain DLHX4 bacterium was selected which based on morphological and biochemistry characteristics, pathogenic causing the wilt disease quickly in cucumber and 16S ribosomal DNA region sequences showed 99.00% similarity to Ralstonia solanacearum. The resulting study was that the 3 strains selected wrere Bacillus DB8.7, DB2.1, DB9.9 which high antagonistic effect on Ralstonia solanacearum by agar well diffusion method. The antagonistic effect of strain DB8.7, DB2.1, DB9.9 were 31.87 mm, 21.89 mm, 21.67 mm. Result of a detailed analysis of 16S rDNA gene segments, strain DB8.7, DB2.1, DB9.9 showed similarity to Bacillus subtilis, Bacillus velezensis, Bacillus amyloliquefaciens.