Outbreak of a New Phytophthora sp Associated with Severe Decline of Almond Trees in Eastern Spain

Since 2007, a decline of young almond trees (Prunus dulers) has been observed in different field-mown nurseries in Valencia (east-central Spain) Early symptoms in affected trees included chlorosis, wilting. cankers. and profuse stem gumming A Phytophthora sp was consistently isolated front cankers, roots. and soil of affected trees It was a heterothallic species with amphigynous and/or paragynous antheridia, and its morphological features did not con form to any of the described Phytophthora species Pathogen city was proved by artificial inoculation. completing Koch's postulates All isolates were sensitive to the phenylamide fungicides metalaxyl and mefenoxam Amplification and sequencing of the internal transcribed spacer (ITS) region, translation elongation factor 1 alpha gene (EF-1 alpha), the beta-tubulin (beta-tub) acne, and the region containing the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene fragment identified the species as Phytophthora taxon "mederhauserii", and phylogenetic analyses placed it in Phytophthora Clade 7b