Distribution and characterization of Botryosphaeriacea species associated with branch dieback and shoot blight on walnut trees in Middle Anatolia Region

In this study, surveys were carried out in 265 walnut locations in the Central Anatolia Region (Yozgat, Sivas, Kırşehir, Kırıkkale, Nevşehir, Niğde, Aksaray, Kayseri) between 2020-2021 in order to determine the species and prevalence rates of Botryosphaeriaceae group disease agents causing diaback, trunk and branch cancer, and trunk discharge in walnut trees and diseased plant tissue samples were collected. The disease prevalence in the Central Anatolia Region was found to be 32.3% on average. Disease prevalence varied among provinces, and the highest prevalence was found in Aksaray province with 54.5%, followed by Kırıkkale (45.7%), Yozgat (40.4%) and Nevşehir (37.5%) provinces, respectively. Disease agents were detected in 86 of 265 locations surveyed and 558 pathogenic Botryosphaeriaceae isolates were obtained. The isolates were identified as Diplodia seriata, Botryosphaeria dothidea and Neofusicoccum parvum according to their conidial morphology, cultural characteristics and base sequence analyses of rDNA-ITS, β-tubulin and EF1-ɑ genes. According to pathogenicity tests, N. parvum, B. dothidea and D. seriata were found to be the most virulent species in walnut trees, respectively.