A PAPILLATE PHYTOPHTHORA SPECIES WITH SPECIFICITY TO RUBUS

The morphology, physiology, protein patterns and pathogenicity of a pa pillate Phytophthora sp. that is widely distributed in raspberry stock s, are described and compared with those of other Group I Phytophthora species, especially P. reclaimer, and with species from other groups that attack raspberry (P. citricola and P. syringae). The papillate sp ecies, although similar to 'typical' isolates of P. cactorum from rasp berry and other hosts, could be distinguished from them on virtually a ll the criteria examined. Distinctive characteristics that separated t hem from P. cactorum isolates were absence of growth patterns on certa in media; persistent sporangia; low rates of growth; low cardinal temp eratures; inability to utilize nitrate nitrogen; host range limited to raspberry but with more severe symptoms; and differences in protein p atterns. It was concluded that these papillate Phytophthora isolates f rom raspberry represent a new species which has been named as Phytopht hora idaei sp. nov.