Mode of antifungal action of a perspective bacterial strain-producer of microbiopreparations 11-3 Bacillus sp. on a pathogen of fusariose on oil flax Fusarium oxysporum var. orthoceras

The search of perspective strains-producers for microbiopreparations creation protecting oil flax of fusariose pathogen have been conducting in the laboratory of Biological methods of the V.S. Pustovoit All-Russian Research Institute of Oil Crops in recent years (2018–2020). These researches contemplate studying of a mode of antagonistic action of the promising strains-producers of microbiopreparations on a disease pathogen. There is presented an interaction between the promising strain-antagonist 11-3 Bacillus sp. selected by a stage screening and the pathogen Fusarium oxysporum var. orthoceras. Modifications of pathogen mycelium were stated at the second day of joint incubation, even before intergrowth with antagonist’s colony. They were as following: formation of spheroplasts (ball-shaped swellings of apical parts of hyphae), their explosion and lining appearance, and compression and discoloration of the separate mycelium plots. After intergrowth of pathogen and antagonist we noted the stronger compression, prolification, thickening and destruction of substrate airy mycelium and chlamidospores of fusariose pathogen. Pathogen’s mycelium at joint cultivation with the bacillary strain-antagonist was totally destructed at the eighth-tenth day.