Diplodia sapinea found on Scots pine in Finland

Abstract

Diplodia sapinea is an important pathogen of Pinus spp. in many parts of the world's temperate and sub‐tropical zones. In Central Europe, this fungus has been known since its first description in the 19th century. But it was only in 2007 that the fungus was identified using DNA‐markers in northern Europe (in Estonia). Viljo Kujala reported observing D. sapinea on logging debris of Norway spruce in Finland in 1945, but we have not been able to verify the identifications from his herbarium samples. In 2004, we collected cones under asymptomatic Scots pine (Pinus sylvestris) trees at one location near the southern coast of Finland but failed to isolate D. sapinea from the samples. In 2015 and 2016, we collected fallen Scots pine cones in 15 Scots pine stands in various parts of Finland and the fungus was found at five locations in southwestern Finland including the location investigated in 2004. Frequency of cones with pycnidia of D. sapinea varied from 1% to 12% in the infested stands. No symptoms of Diplodia tip blight or resinous cankers were detected in trees in the stands where the cones were collected. The results suggest a recent introduction after 2004 of the D. sapinea in Finland.