Résumé
A total of 104 actinomycete isolates were recovered from farming soil samples collected from 11 states in Sudan. Upon screening for potential antifungal activity, an actinomycete isolate (R92) was found to be highly antagonistic against all of the tested phytopathogenic fungi. It was identified as Streptomyces rochei on the basis of its morphology, chemotaxonomy and 16S rDNA sequence analysis. In vivo antagonistic activities of the nbutanol extract of R92 culture were significant since the progress of Drechslera halodes leaf spot on sorghum and Alternaria alternata early blight on tomato was highly restricted and incidence of both diseases was greatly suppressed. Trials to evaluate the In vivo control efficacy of this extract under field conditions is recommended.