Phytophthora Species Infecting Hardy Ornamentals in Nurseries and the Managed Environment in Scotland

Between 2002 and the end of 2009, more than 4000 samples from hardy ornamental plants, collected in surveys for Phytophthora ramorum, were examined to establish the occurrence and diversity of Phytophthora species in Scotland. The samples were gathered from more than 77 plant genera in nurseries, gardens and amenity landscapes. Fifteen different Phytophthora spp. were isolated and identified either by polymerase chain reaction (PCR) or by sequencing of the ITS1, 5.8S subunit and ITS2 region of the ribosomal RNA gene. The most widespread Phytophthora spp. were P. ramorum and P. syringae, followed by P. cactorum, P. kernoviae, P. plurivora, P. cambivora, P. citrophthora, P. taxon ‘Pgchlamydo’, P. pseudosyringae and some single isolates of P. cinnamomi, P. cryptogea, P. gonapodyides, P. nicotianae and P. hibernalis. One isolate did not match any known species. In relation to the number of samples, Phytophthora was found more frequently in trade premises than in gardens or amenity landscapes and the species diversity was higher, highlighting the risks involved in plant trade.