Antifungal action of the perspective strains of the fungal and bacterial antagonists on zoo-sporangia of the downy mildew pathogen on sunflower

Antifungal action of the perspective strains of antagonists T-2 Trichoderma sp., Xk-1-4 Chaetomium olivaceum, B-12 Bacillus licheniformis and Sgrc-1 Pseudomonas fluorescens on zoosporangia of the Downy Mildew pathogen Plasmopara halstedii (Farl.) Berl. et de Toni. on sunflower (race mixture 330, 710, and 730, in a rate 1 : 1 : 1) was studied. The state of zoosporangia of the disease pathogen in mixture with suspensions of antagonists and in control was estimated once after wash-off from the cotyledonous leaves of sunflower seedlings, and in 1; 2.5; 4; 6 and 24 hours at the average temperature 21 °С. In all variants of the mixtures of zoosporangia suspensions and fungal and bacterial antagonists, protoplasm shrinkage has been noted for the most zoosporangia of Downy Mildew pathogen already in first hours (1-2.5 h), and this effect has been keeping till the end of observations. In variants with bacterial strains, unlike the fungal antagonists, protoplasm out from a lot of zoosporangia was observed. In all variants of antagonists and downy mildew pathogen mixtures the same as in control, the most zoosporangia have being performed during 24 h, but in variants with bacteria, especially of Pseudomonas genus, protoplasma was differed by more grainy structure. There was observed no out of zoospores from zoosporangia of downy mildew pathogen in all mixture variants both with fungal and bacterial antagonists. In control, zoospores out in amount 8-10-14 spores (size 7.7-8.4 × 9.2-9.9 um) per a zoosporangium was observed in 1.5-2.5 h after wash-off of formed downy mildew spores, and in another case its amount was equal to more than 100 spores (size 1.2-1.9 × 1.5-2.1 um). Germinated bigger zoospores were noted in control in 2.5-4 h after wash-off of the downy mildew formed spores. Germinated small zoospores of the pathogen were not observed.