Investigation of pistachio saplings in Siirt province regarding soil fungal pathogens

Abstract

Pistachio (Pistacia vera L.) is a significant agricultural product in the Southeastern Anatolia Region, particularly in the province of Siirt. A substantial portion of the region's demand for saplings is fulfilled by nurseries in this province. In this study, the objective was to identify fungal pathogens responsible for root, crown rot, and wilt symptoms, as well as to determine disease prevalence rates in pistachio nurseries located in Siirt province. The incidence of plants exhibiting disease symptoms in the examined nurseries was found to range between 1% and 6%. Since plants showing disease symptoms were observed in each nursery, the prevalence was calculated as 100%. As a result of the survey, 142 fungal isolates belonging to 12 species and 8 genera were obtained. These isolates were identified morphologically and molecularly. As a result of the pathogenicity studies, it was determined that several Fusarium species (F. solani, F. oxysporum, F. verticillioides (Syn. F. moniliforme), F. equiseti, F. avenaceum, F. proliferatum, Fusarium spp.) and Neoscytalidium dimitatum, Rhizoctonia solani, Macrophomina phaseolina, Phoma spp., Cylindrocarpon spp. colonized the pistachio branches, leading to tissue discoloration. According to the symptoms observed on the branches, the most pathogenic fungal isolates were identified as follows: N. dimitatum BŞR9.1, N. dimitatum AKT1.3, F. solani BŞR9.2, F. oxysporum BŞR5.4, M. phaseolina BŞR1.3, and F. equiseti BŞR2.3.1, respectively. Additionally, figures depicting the morphological characteristics and microscopic images of the pathogens are provided.