01952nas a2200205   4500008004100000022001400041245009600055210006900151260001600220300001400236490000800250520129900258100001901557700001601576700002601592700001901618700001901637700002601656856006401682       2011                        eng d  a0031-949X00aPhytophthora ramorum in Canada: Evidence for Migration Within North America and from Europe0 aPhytophthora ramorum in Canada Evidence for Migration Within Nor  cJan-01-2011  a166 - 1710 v1013 a<p>Phytophthora ramorum, the cause of sudden oak death on oak and ramorum blight on woody ornamentals, has been reported in ornamental nurseries on the West Coast of North America from British Columbia to California. Long-distance migration of P. ramorum has occurred via the nursery trade, and shipments of host plants are known to have crossed the U.S.-Canadian border. We investigated the genotypic diversity of P. ramorum in Canadian nurseries and compared the Canadian population with U.S. and European nursery isolates for evidence of migration among populations. All three of the P. ramorum clonal lineages were found in Canada but, unexpectedly, the most common was the NA2 lineage. The NA1 clonal lineage, which has been the most common lineage in U.S. nurseries, was found relatively infrequently in Canada, and these isolates may have been the result of migration from the United States to Canada. The EU1 lineage was observed almost every year and shared multilocus genotypes with isolates from Europe and the United States. Estimation of migration rates between Europe and North America indicated that migration was higher from Europe to North America than vice versa, and that unidirectional migration from Europe to North America was more likely than bidirectional migration.</p>1 aGoss, Erica, M1 aLarsen, Meg1 aVercauteren, Annelies1 aWerres, Sabine1 aHeungens, Kurt1 aGrünwald, Niklaus, J  uhttps://apsjournals.apsnet.org/doi/10.1094/PHYTO-05-10-0133