Method of artificial inoculation of sunflower seedlings with downy mildew pathogen to determi effectiveness of laboratory simples of microbiopreparations based on antagonist strains

We present a modified method of artificial inoculation of sunflower seedlings with downy mildew to determine the effectiveness of microbiopreparations based on antagonist strains under laboratory conditions. We recommend inoculating sunflower seedlings with the downy mildew pathogen in growth chambers filled with sand and lined with filter paper, without removing husks and seed coat from the seeds treated with microbiopreparations. This allows the propagules of microbiopreparations to remain on the seeds and roots of sunflower seedlings for a long time and to manifest their protective effect. In addition, this method allows to obtain uniform sprouts, to exclude sunflower seedlings affected by other pathogens, and to avoid rapid drying of the filter paper, which is unacceptable under downy mildew inoculation, or overwatering, which may contribute to washing off the microorganisms' propagules. If the above conditions are fulfilled, a qualitative evaluation of the effectiveness of laboratory samples of microbiopreparations can be provided for further testing of the best variants in the field.