OCCURRENCE AND HARMFULNESS OF PHYTOPHTHORA SPP. IN POLISH HARDY ORNAMENTAL NURSERY STOCK

The occurrence of Phytophthora species in Polish hardy ornamental nursery stock and their pathogenicity toward some plants were the objectives of this study. P. cinnamomi, P. citricola and P. cryptogea were already isolated in 1993 from diseased Abies spp., Calluna vulgaris, Chamaecyparis lawsoniana, Rhododendron spp. and Pinus spp. During the next 15 years P. cambivora, P. citrophthora, P. nicotianae var. nicotianae and P. ramorum were isolated from ericaceous, coniferous and deciduous plants. P. ramorum was mainly detected in rhododendron but also from Calluna vulgaris, Pieris japonica, Vaccinium vitis-idaea and from Photinia fraseri. The last species used for inoculation caused the development of necrosis on ericaceous plants but also on Sambucus nigra and Viburnum opulus.