Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
1997
Abstract
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.
Abstract
The pathogenicity of the blue-stain fungi Ceratocystis rufipenni Wingfield, Harrington & Solheim and Leptographium abietinum (Peck) Wingf., associated with the spruce beetle (Dendroctonus rufipennis (Kirby)), was evaluated after inoculation of 35 Sitka spruce (Picea sitchensis (Bong.) Carrière) trees at densities of 200, 400, and 800 inoculation points/m2 in a 60-cm band at breast height. Trees were felled 5 months after inoculation to assess fungal infection and pathogenicity. Ten trees inoculated with C. rufipenni at the two highest densities were rated as dead at the time of harvesting whereas all trees inoculated with L. abietinum were rated as surviving or survival uncertain. Inoculation with C. rufipenni produced significantly longer lesions in the phloem and killed significantly more phloem than did L. abietinum. For both fungi, the percentage of dead phloem increased with increasing inoculation density. The percentage of occluded sapwood increased with increasing inoculation density of C. rufipenni, and all sapwood was occluded at 800 inoculations/m2. Inoculation with L. abietinum resulted in approximately 25% occluded sapwood and the occlusion was not affected by inoculation density. Ceratocystis rufipenni may contribute considerably to overwhelm spruce trees infested by D. rufipennis.
Authors
François Lieutier Franck Brignolas Daniel Sauvard C. Galet A. Yart M. Brunet Erik Christiansen Halvor Solheim Alan A. BerrymanAbstract
No abstract has been registered
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Report – PROTOS; Annual report for the first project year
Jan Mulder, E. Matzner, J.F. Gallardo, ...
Authors
Jan Mulder E. Matzner J.F. Gallardo Edward TippingAbstract
No abstract has been registered
Authors
Jan Mulder E. Matzner J.F. Gallardo Edward TippingAbstract
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Authors
Arild Vatn Lars R. Bakken Halstein Lundeby Eirik Romstad Per Kr. Rørstad Arild Vold Peter BotterwegAbstract
This paper analyses a set of policy measures oriented towards reduc ing losses of nitrogen, phosphorus, and soil from agricultural land . An interdisciplinary modelling system- ECECMOD - is presented a nd a set of policy scenarios analysed. The analyses are oriented towards comparing the effects of input-oriented measures (fertilise r taxes) and policy measures directed towards more direct changes in the agronomic practices conducted on the farm. The effects on emission levels, abatement costs, and distributional effect s are documented. The trade-offs between precision and regulation costs are discussed.
Authors
Richard HorntvedtAbstract
No abstract has been registered
Authors
Ian HunterAbstract
No abstract has been registered