Present status of Phytophthora species in the Mediterranean area, especially in relation to citrus1

Of the 44 currently accepted species of Phytophthora, 18 have been reported in the Mediterranean area. The status of each is briefly reviewed. On citrus, P. citrophthora and P. nicotianae var. parasitica are mainly responsible for foot rot and gummosis, and in addition P. hibernalis, P. syringae, P. cifricola and P. cactorum for brown rot of fruits. The incidence of these species is closely linked to their temperature requirements. The use of sour orange as a resistant rootstock has long provided satisfactory control of foot rot and gummosis, while chemical treatments are effective against brown rot. However, there are indications that, with changingcultural practices, the resistance of sour orange is less well expressed, and the species is incidentally also susceptible to citrus tristeza closterovirus. Alternative rootstocks are therefore being sought.