Role of Neopestalotiopsis australis in Needle Necrosis Blight of Stone Pine Saplings in Türkiye

The stone pine (Pinus pinea L.) is a significant forest tree species in Türkiye. Its cultivation takes place in forest nurseries, and it is used in reforestation areas. The objective of this study to determine the causes of blight occurring in stone pine seedling in the Hendek Forest Nursery. Blight symptoms were observed on the needles of 1-2-years-old stone pine seedlings in the Hendek Forest Nursery. Isolates obtained as a result of isolation were identified as Neopestalotiopsis australis based on morphology and by combining sequence data from the LSU, ITS, tef1, and tub2 gene regions. A Maximum Likelihood phylogenetic tree was constructed for two isolates of N. australis based on four loci. Neopestalotiopsis australis was isolated from 25 out of 60 necrotic needles examined. The pathogenicity of N. australis was examined on healthy stone pine saplings by spraying spore suspension. After 28 days following the inoculation with spore suspensions, N. australis caused necrosis on needles. The pathogen was isolated from symptomatic needles in the stone pine the first time in the Türkiye. Neopestalotiopsis australis was proven to be a pathogen on stone pine. It has been concluded that N. australis could pose a threat to stone pine sapling. Further research should be conducted on this fungal pathogen for more detailed insights.