PREVALENCE OF POTATO BLACKLEG AND SOFT ROT IN GEORGIA

Potato is an important crop in Georgia, but the average yields are considerably low (12 t/ha). One of the significant reasons for this is bacterial diseases.  During 2020-2021, 73 samples of diseased potato tubers and stems were collected from fields and storage facilities, in different locations in Georgia. Following microbiological and biochemical tests, 54 strains (70%) were gram-negative, facultative anaerobic, oxidase negative, and catalase-positive, they developed at 37^oC and in 5% NaCl, non-fluorescent on King´s B medium, and produced cavities on Crystal Violet Pectate (CVP) media, thus indicating they were either Dickeya or Pectobacterium spp. 27 out of selected 33 strains were identified as Dickeya spp. using conventional PCR and 21 of them were further characterized as D. solani (using TaqMan RT-PCR). According to the present research, D. solani is the major pathogen associated with potato soft rot and black leg in different regions of Georgia. The most prevalent species in Europe, P. brasiliense, as well as D. dianthicola have not been detected in the current research.