Hopp til hovedinnholdet

Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

1997

Sammendrag

Fungi were isolated from the beetles, Ips typographus f. japonicus and Yezo spruce (Picea jezoensis) trees infested with the beetles in Hokkaido, Japan. Nine species of ophiostomatoid fungi including one new species were identied. They were Ceratocystiopsis minuta, Ceratocystis polonica, Ophiostoma ainoae, O. bicolor, O. cucullatum, O. europhioides, O. penicillatum, O. piceae, and a new species described here as O. japonicum. Based on frequencies of occurrence, O. ainoae, O. bicolor, O. penicillatum, and O. piceae were regarded as dominant associates of I. typographus japonicus, and C. minuta, C. polonica, O. europhinoides, and O. japonicum were subdominant. The species of ophiostomatoid fungi associated with I. typographus japonicus in Japan are almost identical to those associated with I. typographus infesting Norway spruce (P. abies) in Europe. This study improves our knowledge of the biogeography of the ophiostomatoid fungi and the insects with which they are associated.

Sammendrag

Pole-size Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were inoculated with two fungi (Ophiostoma pseudotsugae (Rumb.) von Arx and Leptographium abietinum (Peck) Wingf.) associated with the Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) to evaluate their pathogenicity. Pruning the lowermost 30% of the live crown had no effect on host tree defenses. Inoculation with O. pseudotsugae produced significantly longer lesions in the phloem and resulted in a significantly greater percentage of necrotic phloem than inoculation with L. abietinum. The percentage of occluded sapwood was also greater following O. pseudotsugae inoculations, but the difference was not statistically significant. Individual lesion lengths declined significantly with increasing inoculation density, but the total percentage of necrotic phloem increased significantly. Both fungi appeared to be better adapted to grow in sapwood than in phloem. None of the inoculated trees were dead after 5 months, but some were chlorotic with less than 30% functional sapwood within the inoculation band. The results suggest that these fungi may assist the Douglas-fir beetle in overcoming the defenses of live trees.