Özet:

Neoscytalidium novaehollandiae, a new fungal disease causing cracking and sudden drying out in trunks of Pistachio (Pistacia vera L.), which is economic importance, was reported for the first time in the Southeastern Anatolia Region of Turkey. In this study, infestation rate was determined in 25 villages and 75 orchards in the Pistachio growing areas of Şanlıurfa province Karaköprü, Bozova, Birecik, Halfeti and Ceylanpınar districts. The average infestation rate of the five districts surveyed was found to be 35.88%. The rate of infestation was determined as Bozova 43.68%, Birecik 39.34%, Ceylanpınar 36.07%, Karaköprü 32.25% and Halfeti 28.07%, respectively. During the survey, samples were taken from the trunk and branches of the infected trees and isolated in PDA medium. The fungal agent was then purified, examined microscopically, and molecularly determined by PCR (Polymerase Chain Reaction) using the gene region primers of ITS (Internal Transcribed Spacer), ACT (Actin gene), LSU (Long Sub Unit) and SSU (Small Sub Unit). The genetic characterization was demonstrated and sent for sequence analysis. The resulting nucleotide sequences were registered in GenBank (accession number OL455801 for ITS and accession number OL589617 for LSU). As a result of the sequence and phylogenetic analysis, the fungal agent was verified and found to be as close to Neoscytalidium novaehollandiae with 99% to 99.9% similarity according to ITS and LSU gene region sequence data. The similarity ratio was checked for the ACT and SSU gene regions, however, since there were no records for ACT and SSU genes regions in the gene bank, therefor, no evolution was made. It has been determined that the disease agent causes serious infections mostly in old trees, however, newly developing trees could be under threat.