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In Russian research laboratories for direct testing of soil samples for the presence of zoosporangia of the causative agent of potato wart disease Synchytrium endobioticum (Schilb.) Perc. use the flotation method in carbon tetrachloride (highly toxic preparation). The paper presents the results of approbation and improvement of the method for isolating fungus zoosporangia from soil samples using a suspension of kaolin and 40% calcium chloride solution. This method is recommended by the European Plant Protection Organization’s diagnostic protocol. In order to remove the quarantine from the foci of potato wart disease, along with direct testing of the soil, it is necessary to conduct a laboratory biological test using a potato variety susceptible to scab. The purpose of the work is to test and improve the method for isolating S. endobioticum zoosporangia from soil samples using substances that are non-toxic for personnel (kaolin suspension and 40% calcium chloride solution), as well as elements of a laboratory biological soil test for the absence of viable fungal spores using susceptible potato variety. The article presents experimental data on the development of elements of biological testing to obtain reliable results. Application of the improved method with kaolin and calcium chloride was resulted to allocate the significant amount of target organism spores organism in all soil samples tested, including peaty soil. Detailing was carried out, the elements used in the experiments of the soil biological testing for infestation with S. endobioticum, which were used in the experiments are described in detail, as a result of which quarantine is removed from the foci of potato wart disease. Their usage will allow obtaining reliable results about soil contamination with viable S. endobioticum zoosporangias (damage to more than 50% of plants in positive control), on the basis of which they can be recommended for using in laboratory practice.

This work presents the research results of artificial infection of garden strawberry plants of the Elsanta variety with the phytopathogenic fungus Colletotrichum nymphaeae from the Colletotrichum acutatum complex. Three different ways of infecting strawberry plants were analysed: by injecting the plant rosette, spraying with a spore suspension, and infecting the soil. The study showed that the plants of this variety are susceptible to the C. nymphaeae species. The most susceptible parts of plants were identified: leaf blades, petioles and strawberry rosettes. The most obvious symptoms of infection, caused by C. nymphaeae, were found in case of injecting into the rosette. In this work, the most sensitive and valid laboratory methods for isolating and identifying the causative agent of strawberries anthracnose on the planting material were determined: isolation of the pathogen using the deposit method on the 2 % PGA nutrient medium with the addition of 4 % citric acid and identification by the real-time PCR method using the “Fitoscreen set. C. acutatum complex-PB” (CJSC Syntol, Moscow). The C. nymphaeae species from the C. acutatum complex is a pathogen harmful to strawberry plants, causing rapid damage to leaf blades, petioles and rosettes. In the conducted experiment, the root system of strawberry plants was not affected, and there was no infection in the soil.

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