RESULTS OF APPROBATION AND IMPROVEMENT OF METHODS FOR DETECTION OF RESTING SYNCHYTRIUM ENDOBIOTICUM (SCHILB.) PERC. ZOOSPORANGIA IN SOIL SAMPLES AND BIOTESTING TO REMOVE QUARANTINE FROM OUTBREAKS

Abstract

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.