AbstractBlack stain root disease, caused by the fungusLeptographium wageneri, is a native disease of western North America. It primarily attacks severalPinusspecies andPseudotsuga menziesii.Currently absent from Europe, any accidental introduction or the pathogen could pose a threat to the commercially grown conifers in Europe. To assess the extent of this threat, the susceptibility of nine European and North American conifer species to this disease was examined.