Abstract:

In order to screen antagonists against Phytophthora parasitica var. nicotianae, the plate-confrontation method was used. Actinomycetes strain LY18 isolated from soil samples around healthy tobacco individuals’ roots in tobacco field which broke out tobacco black shank, showed well inhibitory activity to Phytophthora parasitica var. nicotianae. The aseptic filtrate of LY18 mixed into medium plate against Phytophthora parasitica var. nicotianae by reducing mycelium growth 70%. The mycelium of Phytophthora parasitica var. nicotianae in plate added aseptic filtrate of LY18 was degradation by SEM observed. LY18 was identified as Streptomyces rajshahiensis according to its morphology, culture characteristic, chemotaxonomic tests and 16S rDNA analisis.