Determination of fungal pathogens causing root, crown rot and wilt diseases in pistachio nurseries in Siirt province

Pistachio (Pistacia vera L.) is the most important agricultural product of Siirt province. In the pistachio nurseries located in this province, symptoms such as root rot, crown rot and wilt have been observed in recent years, and dying of the plants has been detected. The aim of this study was to determine the fungal soil pathogens that cause these symptoms. A survey studies were carried out during the months of May-August in the 2021-2022 season in all nurseries determined. A total of 16 nurseries were surveyed and the rate of plants showing disease symptoms in the nurseries was found to be between 1% and 6%. Thus, the prevalence rate was found to be 100% in terms of root rot and wilt symptoms in nurseries in Siirt province. Pathogenicity studies were carried out with some fungi selected from isolates isolated from plants showing disease symptoms in nurseries. Pathogenicity was carried out on one-year branches cut from cv. Siirt variety. As a result of this study, some Fusarium species ((F. solani, F.oxysporum, F. moniliforme (Syn. F.verticillioides), F.equseti, Fusarium avenaceaum, Fusarium proliferatum, Fusarium spp.), Neoscytalidium dimitatum, Rhizoctonia solani, Macrophomina phaseolina, Phoma spp, and Cylindrocarpon spp. showed that they could colonize the branches and cause discoloration in the tissues. According to the color lengths of the isolates, the most pathogenic isolates are determinated as N. dimitatum BŞR9.1, N. dimitatum AKT1.3, F.solani BŞR9.2, F.oxysporum BŞR5.4, M. phaseolina BŞR1.3, F.equseti BŞR2.3.1 respectively.