Phenotypic Characterization and Phylogeny of Godronia myrtilli (Anamorph: Topospora myrtilli)—Causal Agent of Godronia Canker on Highbush Blueberry

Godronia canker caused by Godronia myrtilli (Feltgen) J.K. Stone is considered one of the most dangerous diseases of blueberry crops. The purpose of the study was the phenotypic characterization and phylogenetic analysis of this fungus. Infected stems were collected from blueberry crops in the Mazovian, Lublin, and West Pomeranian Voivodships in 2016–2020. Twenty-four Godronia isolates were identified and tested. The isolates were identified on the basis of their morphology and molecular characteristics (PCR). The average conidia size was 9.36 ± 0.81 × 2.45 ± 0.37 µm. The conidia were hyaline, ellipsoid or straight, two-celled, rounded, or terminally pointed. The pathogen growth dynamics were tested on six media: PDA, CMA, MEA, SNA, PCA, and Czapek. The fastest daily growth of fungal isolates was observed on SNA and PCA, and the slowest on CMA and MEA. Pathogen rDNA amplification was performed with ITS1F and ITS4A primers. The obtained DNA sequence of the fungus showed 100% nucleotide similarity to the reference sequence deposited in the GenBank. Molecular characterization of G. myrtilli isolates was performed for the first time in this study.