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.
2013
Authors
Berit Nordskog Jan Netland Håvard Eikemo Halvard Hole Tor-Einar Skog Annette Folkedal Schjøll Guro BrodalAbstract
No abstract has been registered
Authors
Aruppillai Suthaparan Arne Stensvand Knut Asbjørn Solhaug Nils Bjugstad David Gadoury Hans Ragnar GislerødAbstract
No abstract has been registered
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No abstract has been registered
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No abstract has been registered
2012
Authors
Steffi Munack Kathrin Roderer Jurate Kamarauskaite Gabriele Cordara Andre van Eerde Peter Kast Ute KrengelAbstract
No abstract has been registered
Abstract
Winter damage caused by frost is frequently observed on common ash (Fraxinus excelsior) in Norway. In spring 2007, extensive winter damage most likely camouflaged ash dieback caused by Chalara fraxinea. In 2008, ash dieback caused by C. fraxinea had spread to large areas in the southern part of Norway. The disease was widespread in forests and nurseries, but also on roadside trees, and in gardens and parks. In 2009, the disease had spread to new areas; about 30 km into Rogaland county in southwestern Norway and also further into some valleys in southeastern Norway.
Authors
Carl Gunnar Fossdal Nadeem Yaqoob Benedicte Riber Albrectsen Halvor SolheimAbstract
Aspen trees are exposed to a range of attackers and employ varied strategies to reduce their impact. The diversity of responses may have importance for resistance properties at the stand level, and justifies the search for varied defensive strategies in natural populations. We used transcriptomic tools to evaluate diverse responses at the gene activity level in Populus tremula in response to wounding, and to inoculation with two pathogenic fungi (Melampsora magnusiana vs Ceratocystis sp.) that differ in life style (biotroph vs necrotroph) and host tissue requirement (live leaf vs dead wood tissues). Two aspen genotypes from the SwAsp collection with differences in growth and phenolic composition were used to study differences in resistance properties. High defence gene induction, high growth and elevated defence properties toward the biotroph appeared to support each other in this study exemplified in the more resistant SwAsp clone, whereas the more susceptible SwAsp clone was much less responsive to infections, and displayed more symptoms when infected with M. magnusiana. Interestingly, in the more resistant clone wounding gave greater systemic activity of selected candidate genes than when combined with the necrotroph, suggesting that this pathogen has some ability to suppress the induction or translocation of the systemic defence signal in this particular clone.
Abstract
In South-east Norway, several scattered observations of reduced growth and dieback symptoms were observed over the last 20 years in 40-60 years old Norway spruce (Picea abies) trees. Typical symptoms start with yellowing in the top and subsequent dieback downwards from the top. These symptoms are often combined with bark beetle (Ips typographus), honey fungus (Armillaria spp.) infections, and a sudden decrease in diameter and height growth. After about 1-5 years, most of the symptomatic trees are dead.We selected 11 representative stands in six counties. In each stand all trees in ten 250 m2 plots were evaluated, in total about 4000 trees. In each of these 110 plots, one symptomatic and one non-symptomatic tree were investigated in more detail. We measured tree diameter, height, took increment cores and assessed crown condition, wounds, resin flow, stem cracks, bark beetle infection and Armillaria presence. In addition, internode lengths of the last 20 years were measured in two of the stands.Preliminary results of internode lengths and increment cores showed a sudden decrease of height and diameter growth in the symptomatic trees. Many of these trees had a secondary infection of bark beetles and Armillaria. Some years appear to be typical problem years for many of the trees. These years also correspond with summer drought, i.e. negative Palmer drought severity indexes which were estimated for each stand. In comparison, the non-symptomatic trees, growing close to the symptomatic ones, showed none or minor growth reductions and discolouration.Climate change and increased summer drought may worsen spruce dieback problems. Management adaptions are uncertain. We conclude that Norway spruce is sensitive to drought, which reduce the growth and weaken the health, and probably reduce the defence against secondary infections.
Authors
Isabella Børja Jan Svtlík Toril Drabløs Eldhuset Holger Lange Frank Newell Kidder Douglas Lawrence GodboldAbstract
No abstract has been registered
Abstract
Damage by cone and seed insects is a severe impediment to those producing conifer seeds in seed orchards. The SNS-supported network `Nordic cone and seed insects` has been cooperating to address this problem since 2007. One of the outcomes is the coordinated monitoring of the most important insect species. The data collected form a basis for establishing strategies for pest management.