Determination of the phytophthora species causing root and collar rot of pomegranate trees in Antalya and Muğla provinces and reactions of some pomegranate cultivars

In this study, Phytophthora species which cause drying in pomegranate trees in Antalya and Muğla provinces where approximately 40% of our country's pomegranate production is made has been determined. Surveys were carried out in 113 pomegranate orchards covering 1703 da. A total of 51 root and 136 soil samples were taken from symptomatic trees. A total of 98 isolates of Phytophthora spp. were obtained from 19 root tissues and 79 soil samples. Phytophthora species were identified based on their morphological characteristics and DNA sequences. The species most frequently isolated were P. nicotianae (37 isolates) and P. palmivora (26 isolates) followed by P. parvispora (14 isolates), P. inundata (6 isolates), P. cryptogea (4 isolates), P. niederhauserii (4 isolates), P. taxon walnut (2 isolates) and P. rosacearum (1 isolate). Identification of 4 isolates could not been confirmed. P. nicotianae, P. palmivora, P. parvispora and P. inundata were isolated from both roots and soil, while the other species were obtained only from soil. Disease incidences were determined as 4.49 %and 5.03% in Antalya and Muğla provinces, respectively. In the pathogenicity test performed with soil infestation method, all isolates caused root rot in pomegranate seedlings ranging from 20% to 85%. This is the first report of all species with the exception of P. palmivora, causing root and collar rot of pomegranate trees worldwide. In addition, the susceptibility of 10 different pomegranate cultivars to P. nicotianae and P. palmivora, which were determined as the most common species, were investigated. Hicaznar, Katırbaşı, Aşınar, Fellahyemez, İzmir 1513, İzmir 23, BATEM Esinnar, BATEM Hicrannar, BATEM Yılmaznar and BATEM Onurnar cultivars were used in this experiment and soil infestation test was used. At the end of the experiment, it was concluded that all cultivars were susceptible to the pathogens and P. nicotianae was more aggressive than P. palmivora.