Turkish Journal of Forestry (Sep 2021)
Incidence of Diplodia sapinea in Pinus nigra subsp. pallasiana and Pinus sylvestris seed
Abstract
Diplodia sapinea, the causal agent of Diplodia shoot blight, is one of the most common and dangerous necrotrophic pathogen of pines worldwide. Movement of plant materials such as cones, seeds and seedlings infected with the pathogen plays an important role in the dissemination of the disease over long distances. While the incidence and damage caused by the pathogen is increasing in Turkey, to our knowledge, the presence of the pathogen on pine seeds and the risk of transmission to nurseries and forest areas through seed movement have not been studied before. This study was carried out between 2017 and 2018 in order to investigate the presence and incidence of Diplodia sapinea in Anatolian black pine (Pinus nigra subsp. pallasiana) and Scots pine (Pinus sylvestris) seeds collected from four abandoned seed orchards in Turkey. Seeds obtained from an active P. nigra seed orchard and a P. sylvestris seed stand were also included in the study. D. sapinea was detected on both P. nigra and P. sylvestris seeds collected from the abandoned seed orchards. On average 70% of the seeds (72% and 57% for P. nigra and P. sylvestris respectively) were infected with the pathogen. The pathogen was not detected on seeds from the active P. nigra seed orchard, yet was detected on 0.50% of seeds from the P. sylvestris seed stand. Thousand-seed-weights as well as germination of seeds from the abandoned seed orchards were lower than those of active seed sources. Taken together, these findings suggest that D. sapinea could have an important role in the reduction of seed quality in the abandoned seed orchards. More importantly, results confirm the potential for dissemination of D. sapinea on P. nigra and P. sylvestris seeds.
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