Occurrence of Phytophthora spp. in Polish rivers and pathogenicity of iso-lates toward some plants were studied. Rivers Jasieniec, Pisia and Rawka were surveyed during all the year with one month interval. First 2 rivers are situated in horticultural areas in Warsaw and Łódź districts whereas the third one is running through agricultural fields and forests. Rhododendron leaves were used as the baits for detection of Phytophthora from water. Number of necrotic spots on baiting leaves was a measure of population densities of Phytophthora spp. in rivers. The occurrence of Phytophthora in water was noticed during all year with the lower density in the 3rd quarter of the year. Five Phytophthora species and taxon Salixsoil were identified among isolates recovered from 3 rivers. During all year from 3 surveyed rivers (except from Pisia in the first quarter) P. citricola was recovered as the most often occurring species. Additionally P. cactorum, P. cambivora, P. cinnamomi and P. megasperma were detected from rivers. In laboratory trials water isolates of P. cactorum and P. citricola colonized roots, stem parts and leaves of birch with the significantly faster spread of necroses on plant parts inoculated by P. citricola. In greenhouse trial both species caused root ...
Qualification of Phytophthora by Zentmayer as the destructive factor for plants indicates on that group of pathogens as very dangerous. Results obtained from previous studies showed on Phytophthora species as the threat of all group of plants growing in open field, under covering and natural ecosystem. Phytophthora spp. were detected in all analyzed water sources such as water reservoirs and canals localized in nurseries and in rivers flowing through horticulture, agriculture and forest areas. Results of the studies indicate on P. plurivora, P. cambivora, P. cinnamomi, P. citrophthora, P. cryptogea, P. lacustris and P. megasperma as the dominant species in Polish watercourses and reservoirs. Obtained results confirmed the pathogenicity of Phytophthora isolates received from different water sources ...
Utilisation of plants or their parts for detection of Phytophthora from soil and water was the interesting object in the second part of XX century. Using of fruits, seedlings, seeds of different plant species gave possibility to detect the most dangerous pathogens. In this study the effectiveness of rhododendron leaves as the bait for detection of Phytophthora, Cylindrocladium scoparium, formae spec. of Fusarium oxysporum and Rhizoctonia solani from water and horticultural substrate was estimated. During the detection of Phytophthora from river, canal and water container rhododendron top leaves were placed on the surface of water and after 4-5 days number of necrotic spots/leaf was estimated. Parts of necrotic spots were transplanted on PDA medium for isolation and identification of species. In the detection of other species from substrate, rhododendron leaves were placed in the water suspension of soil and after 3-5 day-incubation number of necrotic spots /leaf was calculated. The necrotic spot parts were transferred on PDA medium for isolation and identification of fungal species. Results obtained indicated on rhododendron leaves as satisfactory bait for detection of the most dangerous pathogens from water and soil. The method is easy for application and may be used for all year ...
