Identification of Phytophthora spp. isolated from plants and soil samples on strawberry plantations in Poland

Crown and leather rot of strawberry caused by Phytophthora spp. are major soil diseases of cultivated strawberry (Fragaria x ananassa) in Poland. In this study, in total 45 isolates of Phytophthora spp. from plants of cultivars Elsanta, Honeoye, Florence, Camarosa, Roxana, Onebor, Alba, Elegance, Albion, Senga Sengana and Malwina originating from crowns (20 isolates) and fruits (25 isolates) as well as 25 soil samples from the same fruiting strawberry plantations located in central, northeastern, and south-eastern regions of Poland were identified. Among them, 44 isolates from plant organs and eight from soil samples were identified as Phytophthora cactorum and from one plant and one soil sample as P. citricola; of those remaining from the soil, one was identified as P. citrophthora and one as P. cryptogea. Identifications were based on morphological characteristics and DNA analyses. Species-specific polymerase chain reaction confirmed the presence of Phytophthora spp. in all positive examined plant and soil samples and confirmed that P. cactorum is predominantly responsible for crown and leather rot diseases of strawberry in monitored regions of Poland. Pathogenicity tests showed that all isolates of Phytophthora spp. originating from soil derived from strawberry plantations were pathogenic both to strawberry and to raspberry.