This study dealt with the species distribution and frequency of fungi associated with the bark beetle Ips typographus (Scolytidae) on spruce trees of various states of health in southern Poland. The spruce trees were assessed by their degree of defoliation and damage of their crowns and trunks after attack by I. typographus. The state of health of trees from which samples were obtained was related to varying stages of brood development of I. typographus. Fungi were isolated from phloem taken from and around insect galleries and the sapwood underneath brood systems. Samples were taken from Ôhealthy-lookingÕ, weakened, wind-fallen and wind-broken trees as well as from trap trees. The mycobiota associated with I. typographus was quite diverse in respect of the number of detected species, 65 fungal taxa were obtained from the phloem of trees infested by I. typographus, and 36 taxa occurred in the sapwood underneath insect galleries. The spectrum of fungi mainly consisted of ascomycetes and anamorphic fungi. The ophiostomatoid fungi were represented by 14 species and were the most numerously represented group in all niches examined. The most frequent ophiostomatoid species were Ceratocystis polonica, Ophiostoma ainoae, O. bicolor, O. penicillatum, O. piceae and O. piceaperdum. The frequency of occurrence of ophiostomatoid fungi differed significantly between the phloem and sapwood as well as in relation to the varying states of health of the spruce trees. These quantitative differences in the mycobiota of I. typographus between spruce trees belonging to different health categories can be explained by successional patterns of fungal colonization of host tissues following attack by I. typographus. The pathogenic species C. polonica was the primary invader, occurring most frequently in the sapwood of Ôhealthy-lookingÕ trees. Ophiostoma bicolor, O. penicillatum and O. piceaperdum also occurred during the early stages of brood development of I. typographus on Ôhealthy-lookingÕ trees, but they mainly colonized the phloem. In contrast, O. ainoae, O. minuta and O. piceae likely follow the aforementioned species as secondary and tertiary invaders into the phloem and the sapwood of spruce trees.

-The species composition and virulence of fungi associated with Tomicus piniperda were studied at eight locations in Poland. The fungi were isolated from phloem and sapwood samples taken from insect galleries and then identified. The virulence of the most common ophiostomatoid species was evaluated through inoculations using two-year-old Scots pine seedlings. A great diversity of fungi were found associated with T. piniperda, including 4 837 cultures and 67 species. The most important groups of fungi were the ophiostomatoids and moulds, including mainly Penicillium, Trichoderma and Mucor species. Among ophiostomatoid fungi, Ophiostoma minus and O. piceae dominated, with a frequency of occurrence of 32.4 and 11.5% of inspected galleries, respectively. Occasionally isolated species included Leptographium lundbergii, L. procerum, L. wingfieldii, Graphium pycnocephalum and Graphium sp. 'W'. In general, the frequency of the ophiostomatoid species was highly variable among locations. Leptographium wingfieldii and O. minus, were the only species capable of killing whole plants and penetrated deeper into the sapwood than other species (87-100% mortality during the 11 week incubation period). Other fungi, including O. piliferum, O. piceae and L. procerum, were considerably less virulent.

Fungi from the genus Geosmithia (Ascomycota: Hypocreales) are associated with bark beetles (Coleoptera: Scolytinae), though little is known about ecology, diversity, and distribution of these fungi across beetle and its host tree species. This study surveyed the diversity, distribution and vector affinity of Geosmithia isolated from subcortical insects that colonized trees from the family Pinaceae in Central and Northeastern Europe. Twelve Geosmithia species were isolated from 85 plant samples associated with 23 subcortical insect species (including 14 bark beetle species). Geosmithia community composition was similar across different localities and vector species; although the fungal communities associated with insects that colonized Pinus differed from that colonizing other tree species (Abies, Larix, and Picea). Ten Geosmithia species from four independent phylogenetic lineages were not reported previously from vectors feeding on other plant families and seem to be restricted to the vectors from Pinaceae only. We conclude that presence of such substrate specificity suggests a long and stable association between Geosmithia and bark beetles.

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