Eighty six Phlebiopsis gigantea isolates from at least 9 different tree species from various locations in 12 different European countries and North America were screened for the presence of large molecular weight dsRNA >10 kbp in size. In 7 isolates, which contained large dsRNAs, the presence of Phlebiopsis gigantea large virus-1 (PgLV-1) was suggested following the sequencing of the RT-PCR amplicons generated with PgLV-1 specific oligonucleotide primers which also revealed little genetic diversity between the virus isolates.