EN
Valdensia heterodoxa as a parasitic fungus was observed on Ericaceae family plants i.e. blueberry (Vaccinium corymbosum L.), bilberry (V. myrtillus L.) and lingonberry (V. vitis-idaea L.). Isolates of this polyphagous were obtained from the infected leaves of different cultivars of highbush blueberry collected from commercial plantation in Mazovia province and from bilberry collected from forests in Pomerania province. PCR amplification of selected rDNA fragments (ITS1, 5.8S, ITS2) was done with ITS1F and ITS4A primers. Bioinformatic analysis revealed similarity 99–100% between selected nucleotide sequences of V. heterodoxa isolates from bilberry and highbush blueberry. The sequences of bilberry isolates were obtained and described for the first time in Poland. Their reference sequence was deposited in GenBank (KT121733). In laboratory experiments conidia of selected bilberry isolates on OA medium were 278 ±6 × 140 ±4 μm. Conidia from highbush blueberry, bilberry, and lingonberry were measured. Depending on the host plant conidia were different in the length of the arms and width of the head. The growth of the fungal isolates on PDA (potato dextrose agar), OA (oatmeal agar), WOA (weak oatmeal agar), SNA (salt nutrient agar) media was examined. The cultures were divided into two groups based on their morphology on PDA medium.