Severity of Diplodia shoot blight (caused by Diplodia sapinea) was greatest on Pinus sylvestris and Pinus nigra in a plantation containing five pine species

Abstract

The severity of Diplodia shoot blight in Pinus nigra and P. sylvestris seed orchards, and in P. taeda, P. pinaster and P. radiata industrial plantations was examined in two 20 × 20 m plots of each tree species. All 159 trees assessed in the plots showed symptoms of Diplodia sapinea infections. Average disease severity in the tree crowns varied from 42 to 68% (mean = 53.8%) over all tree stands. Fungus isolates obtained from affected trees were identified as D. sapinea, based on morphological characteristics of cultures and conidia grown on agar plates. The identifications were confirmed by sequence analysis of the ITS rDNA of a subsample of isolates. Multilocus genotyping with RAMS primers showed that 13 D. sapinea genets were present in the plots. Diplodia sapinea had serious impacts on P. sylvestris and P. nigra in the seed orchards Marmara Region of Turkey, and is likely to have been the main causal agent of shoot blight and reductions in seed production at this location.