Determination of the Prevalence and Morphological Identification of the White Rot Pathogen (Sclerotinia sclerotiorum (Lib.) de Bary) in Sunflower in Erzurum Province

Sunflower (Helianthus annuus L.) is an important crop grown in Turkey for both oil and confectionerypurposes. In recent years, changes in climatic conditions and variations in planting patterns haveincreased the incidence of diseases in sunflower crops in Erzurum, leading to significant economiclosses. Among these diseases, white rot caused by Sclerotinia sclerotiorum (Lib.) de Bary results indecay of the roots, stems, and capitulum tissues, causing reductions in both yield and quality. Thepathogen can survive in the soil for extended periods through its resilient structures, called sclerotia, andcan initiate infection again under favorable environmental conditions. In this study, the prevalence ofthe white rot pathogen in sunflower fields in Erzurum was investigated. Field surveys were conductedin the districts of Pasinler, Horasan, Yakutiye, Aziziye, Aşkale, and Palandöken. Samples were collectedfrom symptomatic sunflower plants, transported to the laboratory, and cultured in vitro on PotatoDextrose Agar (PDA) medium. Pure cultures were obtained from the developing colonies. Macroscopicand microscopic observations of the isolates confirmed their identity as Sclerotinia sclerotiorum. Theresults indicated that white rot disease occurred at varying intensities across all surveyed districts ofErzurum Province. However, the disease was observed to be more severe in Aziziye and Pasinler, whilelower levels were recorded in Horasan, Yakutiye, Aşkale, and Palandöken. This study provides an upto-date and region-specific assessment of the prevalence of Sclerotinia sclerotiorum in sunflowercultivation areas of Erzurum and establishes a solid scientific foundation for future research on thepathogenicity, epidemiology, and molecular characterization of the pathogen.Keywords: Sunflower, Sclerotinia sclerotiorum, Erzurum, Morphological Identification