In-Vitro Antagonistic Effect of Bacillus thuringiensis on Ralstonia solanacearum, the Causal Agent of Bacterial Wilt Disease of Tomato (Lycopersicon esculentum Mill).

Tomato (Lycopersicon esculentum, Mill) is a rich source of vitamins, minerals and lycopene, which has many health benefits. However, its production hampered by bacterial wilt caused Ralstonia solanacearum resulting in significant yield losses. Use chemicals the control plant pathogens detrimental effects on humans environment terms leaving residues soil later find their way into underground waters. Therefore, it desirable to an alternative chemical this pathogen. This study investigates potential native Bacillus thuringiensis (Bt) for biological (Rs) under laboratory conditions. B. was isolated from cultivated soil, non- stagnant water, sawdust, horse dung, grain dust, dead leaves poultry manure. R. stem exudates infected plants pathogenicity assay carried out using 2-week-old seedlings Beske tomato variety. The Bt isolates were then characterized phenotypically. further identified endospore parasporal staining techniques. All tested in-vitro antagonistic activity agar well diffusion method. Isolates Bt2, Bt16, Bt17, Bt32 Bt34 confirmed as while isolate Rs solanacearum. showed wilting symptoms fourth day inoculation eventual death seedlings. zone inhibition exhibited ranged 0.0 mm 20.0 mm.
 Keywords: thuringiensis, In-vitro, Bacterial wilt, solanacearum,