Importance of antibiotic production in antagonism of selected XXXX species to two soil-borne plant pathogens.

@entity3587 @entity10644 @entity13891 @entity1460
Antagonism of ten @entity10644 spp., five of which produce antibiotics, to the plant pathogens Rhizoctonia solani and Phytophthora megasperma var. sojae was studied. Antibiotic activity was detected in culture for the five antibiotic producers. @entity10644 , @entity13891 . geldanus, and S. noursei produced wide zones of inhibition to R. solani and P. megasperma var. sojae. Similar activity was found for S. reticuli var. protomycicus to P. megasperma var. sojae. S. cellulosae reduced Rhizoctonia root rot on @entity3587 when sterile soil was infested simultaneously with the antagonist and R. solani. @entity13891 gave almost complete disease control when the streptomycete was added 7 days prior to infesting the soil with R. solani. Several of the @entity10644 spp. reduced Phytophthora root rot on @entity1460 when the streptomycetes were added to soil at the same time as P. megasperma var. sojae or 7 days prior to adding the pathogen. S. herbaricolor and S. coeruleofuscus gave the most consistent control. No relationship was found between reported antibiotic activity or antagonism on agar media and reduction in disease severity. Only @entity13891 . geldanus gave both control of Rhizoctonia root rot and large zones of inhibition on agar media when the streptomycetes were preincubated in soil for 7 days.
