[Search for actinomycetes--antagonists of fungi causing sugar beet root rot]

Actinomycetes belonging to Streptomyces were isolated from the rhizosphere of sugar beet grown on an infected area after cultivation for many years. 44.1 per cent of them proved to be antagonists of phytopathogenic test fungi. The majority of the antagonists were detected among the Cinereus. The lowest number of the antagonists was detected among the Azureus, the maximum number of the antagonists was observed in the middle and at the end of the sugar beet vegetation period. During various periods of the plant development, the number of the antagonists belonging to different sections changed. The majority of the actinomycetes belonging to Streptomyces were active against Fusarium solani and Botrytis cinerea. The antagonists of the fungi were mainly detected among the representatives of the Cinereus and Helvolo-Flavus.