Seedlings of Scots pine(Pinus sylvestrisL.) and lodgepole pine(P. contortaDougl.) provenances, as grown in Finland, were inoculated with “m”; and “r”; “forms”; of the pinewood nematode (Bursaphelenchus xylophilus)from Canada, anmform isolate from France and anrform isolate from Missouri, USA. Scots pine was highly susceptible to an Albertarform and a British Columbiamform isolate and moderately susceptible to two Quebecmform isolates. Lodgepole pine was higly susceptible to the tworform (Alberta and Missouri) isolates and moderately susceptible to the British Columbiamform and the two Quebecmform isolates. Mortality of both pines after inoculation with the French isolate was inconsistent. Mortality of both pines occurred more rapidly following inoculation withrform than with m form nematodes. Large numbers of nematodes were generally found in the tissues of both pines. Our results with seedlings need to be corroborated by inoculating larger field‐grown trees.