First Report of Phytophthora Inflata in Polish Rhododendron Nursery

Abstract

First Report of Phytophthora Inflata in Polish Rhododendron Nursery Phytophthora inflata Caros & Tucker was detected together with P. citricola Sawada from rhododendron cv. University of Helsinki with necrotic spots on leaves. Spots were enlarged on tip parts of the stems. The rhododendron plantswere taken from hardy ornamental stock. Inoculation of the leaf blades of 15 species and cultivars of rhododendron with P. inflata and P. citricola resulted in the development of necroses on all of them. Reaction of tested rhododendron species and cultivars for P. inflata and P. citricola was similar. The pathogen also colonized leaf blades of Goultheria decumbens, Kalmia ostroseptice, Vaccinium corymbiferum and V. vitis-idaea. The quickest spread of necroses was observed on K. ostroseptice and V. corymbiferum. In greenhouse trials P. citricola and P. citrophthora caused dieback of more rhododendron plants than P. inflata.