Some soilborne pathogens causing root rot and wilting of pistachio trees in southeastern Turkey

Abstract

Soilborne fungal pathogens that cause root rot, wilting and dying are the most important problems in pistachio production. The purpose of this study was to examine, isolate, and diagnose the pathogens from diseased pistachio trees in orchards and nurseries located in southeastern Turkey. Fungi isolated from the pistachio trees were identified by morphology and the sequences of the internal transcribed spacer (ITS) region and translation elongation factor-1 alpha (TEF-1 alpha). Fusarium solani, Fusarium oxysporum, Fusarium brachygibbosum, Fusarium chlamydosporum and Macrophomina phaseolina were the most important fungi causing root rot, wilting and decline of pistachio trees. Pathogenicity studies showed that all of the fungi identified can colonize and damage the vascular tissues of a sapling and cause substantial lesions and vascular discolourations. This study provides the first evidence of wilting due to the root and crown rot in pistachio trees in Siirt province of Turkey caused by some Fusarium species, especially F. solani, F. oxysporum, F. chlamydosporum, F. brachygibbosum and M. phaseolina. Finally, the research enabled the identification of some fungal pathogens that are seriously harming pistachio trees in southeastern Turkey.