Pathogenicity of 11 Phytophthora species on CAB-6P cherry rootstock

Abstract

The pathogenicity and virulence of 11 Phytophthora spp. isolated from various hosts were evaluated on CAB-6P cherry rootstock. Isolates of P. cactorum, P. cryptogea, P. citrophthora, P. citricola, and isolate 1143 of P. nicotianae were pathogenic by all three test methods. An in vivo test using bark strips did not distinguish between the isolates in relative virulence and an excised twig test showed P. cactorum and P. cryptogea to be more virulent than the other species. Trunk inoculation ranked the pathogenic species in the order given above. P. capsici, P. cambivora, P. boehmeriae, P. drechsleri, P. palmivora, P. erythroseptica, and isolate 1258 of P. nicotianae were not pathogenic on CAB-6P cherry rootstock. The identity and variability of Phytophthora spp. is important when considering strategies for applying an integrated program to control crown rot of cherry trees. © 2003 Taylor & Francis Group, LLC.