Ophiostomatoid fungi associated with root-feeding bark beetles on Scots pine in Poland

Ophiostomatoid fungi are known to be associated with various species of bark beetles. However, information about fungal associates of root-feeding bark beetles in Europe is still fragmentary. For this reason, the fungal associates of Hylastes ater, H.opacus and Hylurgus ligniperda on Pinus sylvestris were isolated and identified. A total of 743 fungal isolates were collected and separated into 10 morphological groups. Analyses of ITS rDNA and partial -tubulin gene sequences confirmed that these groups represented distinct species. The 10 species included a total of 13 associations between fungi and bark beetles that had not been recorded previously. All of the bark beetles examined were frequently associated with ophiostomatoid fungi. The fungal diversity and relative abundance of species were very similar in the three species of root-feeding bark beetles. The most commonly encountered associates of these beetles were Grosmannia radiaticola, Leptographium lundbergii, L.procerum and L.truncatum. Insect infestation data furthermore suggest that Hylastes spp. and Hg.ligniperda are also important vectors of the fungal pathogen Sphaeropsis sapinea.