Fungi associated with three common bark beetle species in Norwegian scots pine forest

Abstract

Pityogenes bidentatus, P. quadridens and Ips acuminatus are known to be associated with fungi. However, little is known about the associations between the three beetle species and fungi in Norwegian Scots pine forest. This study reports species associated with the three beetle species in Norway. In total, 60 specimens P. bidentatus, 66 of P. quadridens, and 30 of I. acuminatus were collected and dissected. A total number of 560 fungal isolates including 46 species were obtained. In this study, ten ophiostomatoid species were found in association with the three investigated bark beetle species. Pityogenes bidentatus was found to be associated with 24 species of fungi. Five of these species were ophiostomatoid fungi. These were Graphilbum sp.1, Grosmannia europhioides, Ophiostoma ips, O. minus and O. sp. 1. Graphilbum sp.1 was the most abundant species, found in 31.7% of the samples. Two other fungi species with high frequency of occurrences were Fuscoporia sp.1 (15%) and Geosmithia sp.1 (20%). Pityogenes quadridens was found to be associated with 30 species of fungi. Six of these species were ophiostomatoid fungi. These were Leptographium chlamydatum, Graphilbum sp.1, Grosmannia olivacea, O. bicolor, O. minus and O. saponiodorum. However, these were isolated in low frequency. The species with highest frequency of occurrences were Allantophomopsis sp.1 (31.8%), Geosmithia sp.1 (31.8%) and Phacidiopynis sp.1 (30.3%). Ips acuminatus was found to be associated with eleven species of fungi. Four of these were ophiostomatoid fungi. These were Graphilbum sp. 1, Graphium sp. O. minus and O. macrosporum. The fungi with highest frequency of occurrences were Graphilbum sp. 1 (87%) and Phoma spp. (60%). Some of the ophiostomatoid species found in this study have not been registered in Norway before. Ophiostoma sp. 1 might be a new species and not yet described. Graphilbum sp.1 and Geosmithia sp.1 are undescribed species that are found in other studies.