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.
2020
Authors
Ranjana Pathak Åshild Ergon Arne Stensvand Hans Ragnar Gislerød Knut Asbjørn Solhaug Lance Cadle-Davidson Aruppillai SuthaparanAbstract
No abstract has been registered
Authors
Arne StensvandAbstract
No abstract has been registered
Authors
Arne StensvandAbstract
No abstract has been registered
Abstract
The major part of Norwegian apples is marketed within 3-4 months after harvest. ‘Summerred’ is a popular medium early cultivar in Norway, however, it is known to soften quickly during storage and marketing. Storing apples in low temperature and low oxygen atmosphere will slow down the ripening and the fruit will keep green and firm. Delayed cooling has been reported to reduce susceptibility to develop physiological disorders like scald. The experiment included different strategies in delaying cooling (5 days at 7°C) and allowing the apples to reach 1 kPa oxygen storage after an intermediate period (5 days) at 3 kPa oxygen. The main focus was on changes in firmness, degreening, scald and fruit rots. The apples were stored for 3, 6 or 9 weeks in 1 or 4°C and analyzed for standard fruit quality factors (color, firmness, IAD-index, starch, soluble solids content and titratable acidity) as the samples were removed from low temperature and low oxygen storage and after a week at 20°C in regular atmosphere (shelf life). Physiological disorders and fruit rots were registered. In these experiments the fruit quality changes were greater (poorer quality) in apples kept at 7°C for 5 days before storage at 1 or 4°C compared to apples stored immediately at low temperature. The intermediate storage in 3 kPa oxygen tended to make the apples keep firmer during storage. The stepwise reduction in oxygen content reduced the negative effect of delayed cooling. Delayed cooling slowed the starch degradation. The incidences of soft scald and fruit rots were low, and the effects of delayed cooling and/or delayed low oxygen storage were weak.
Authors
Hanno Sandvik Olga Hilmo Snorre Henriksen Reidar Elven Per Arvid Åsen Hanne Hegre Oddvar Pedersen Per Anker Pedersen Heidi Solstad Vigdis Vandvik Kristine Bakke Westergaard Frode Ødegaard Sandra Charlotte Helene Åström Hallvard Elven Anders Endrestøl Øivind Gammelmo Bjørn Arild Hatteland Halvor Solheim Björn Nordén Leif Sundheim Venche Talgø Tone Falkenhaug Bjørn Gulliksen Anders Jelmert Eivind Oug Jan Henry Sundet Elisabet Forsgren Anders Gravbrøt Finstad Trygve H. Hesthagen Kjell Harald Nedreaas Rupert Wienerroither Vivian Husa Stein Fredriksen Kjersti Sjøtun Henning Steen Haakon Hansen Inger Sofie Hamnes Egil Karlsbakk Christer Magnusson Bjørnar Ytrehus Hans Christian Pedersen Jon Swenson Per Ole Syvertsen Bård Gunnar Stokke Jan Ove Gjershaug Dag Dolmen Gaute Kjærstad Stein Ivar Johnsen Thomas Correll Jensen Kristian Hassel Lisbeth GederaasAbstract
1. Due to globalisation, trade and transport, the spread of alien species is increasing dramatically. Some alien species become ecologically harmful by threatening native biota. This can lead to irreversible changes in local biodiversity and ecosystem functioning, and, ultimately, to biotic homogenisation. 2. We risk-assessed all alien plants, animals, fungi and algae, within certain delimitations, that are known to reproduce in Norway. Mainland Norway and the Arctic archipelago of Svalbard plus Jan Mayen were treated as separate assessment areas. Assessments followed the Generic Ecological Impact Assessment of Alien Species (GEIAA) protocol, which uses a fully quantitative set of criteria. 3. A total of 1519 species were risk-assessed, of which 1183 were species reproducing in mainland Norway. Among these, 9% were assessed to have a severe impact, 7% high impact, 7% potentially high impact, and 49% low impact, whereas 29% had no known impact. In Svalbard, 16 alien species were reproducing, one of which with a severe impact. 4. The impact assessments also covered 319 so-called door-knockers, i.e. species that are likely to establish in Norway within 50 years, and 12 regionally alien species. Of the door-knockers, 8% and 10% were assessed to have a severe and high impact, respectively. 5. The impact category of most species was driven by negative interactions with native species, transformation of threatened ecosystems, or genetic contamination. The proportion of alien species with high or severe impact varied significantly across the different pathways of introduction, taxonomic groups, time of introduction, and the environments colonised, but not across continents of origin. 6. Given the large number of alien species reproducing in Norway and the preponderance of species with low impact, it is neither realistic nor necessary to eradicate all of them. Our results can guide management authorities in two ways. First, the use of quantitative assessment criteria facilitates the prioritisation of management resources across species. Second, the background information collected for each species, such as introduction pathways, area of occupancy and ecosystems affected, helps designing appropriate management measures.
Authors
Hanno Sandvik Olga Hilmo Snorre Henriksen Reidar Elven Per Arvid Åsen Hanne Hegre Oddvar Pedersen Per Anker Pedersen Heidi Solstad Vigdis Vandvik Kristine Bakke Westergaard Frode Ødegaard Sandra Charlotte Helene Åström Hallvard Elven Anders Endrestøl Øivind Gammelmo Bjørn Arild Hatteland Halvor Solheim Björn Nordén Leif Sundheim Venche Talgø Tone Falkenhaug Bjørn Gulliksen Anders Jelmert Eivind Oug Jan Henry Sundet Elisabet Forsgren Anders Gravbrøt Finstad Trygve H. Hesthagen Kjell Harald Nedreaas Rupert Wienerroither Vivian Husa Stein Fredriksen Kjersti Sjøtun Henning Steen Haakon Hansen Inger Sofie Hamnes Egil Karlsbakk Christer Magnusson Bjørnar Ytrehus Hans Christian Pedersen Jon Swenson Per Ole Syvertsen Bård Gunnar Stokke Jan Ove Gjershaug Dag Dolmen Gaute Kjærstad Stein Ivar Johnsen Thomas Correll Jensen Kristian Hassel Lisbeth GederaasAbstract
No abstract has been registered
Authors
Mohamed Ibrahim Mohamed Abdelhalim May Bente Brurberg Ingerd Skow Hofgaard Odd Arne Rognli Anne Marte TronsmoAbstract
Microdochium majus and Microdochium nivale cause serious disease problems in grasses and cereal crops in the temperate regions. Both fungi can infect the plants during winter (causing pink snow mould) as well as under cool humid conditions during spring and fall. We conducted a pathogenicity test of 15 M. nivale isolates and two M. majus isolates from Norway at low temperature on four different grass cultivars of Lolium perenne and Festulolium hybrids. Significant differences between M. nivale isolates in the ability to cause pink snow mould were detected. The M. nivale strains originally isolated from grasses were more pathogenic than isolates from cereals. The genetic diversity of M. nivale and M. majus isolates was studied by sequencing four genetic regions; Elongation factor-1 alpha (EF-1α), β-tubulin, RNA polymerase II (RPB2) and the Internal Transcribed Spacer (ITS). Phylogenetic trees based on the sequences of these four genetic regions resolved M. nivale and M. majus isolates into separate clades. Higher genetic diversity was found among M. nivale isolates than among M. majus isolates. M. nivale isolates revealed genetic differences related to different host plants (grasses vs. cereals) and different geographic regions (Norway and UK vs. North America). Sequence results from the RPB2 and β-tubulin genes were more informative than those from ITS and EF-1α. The genetic and phenotypic differences detected between Norwegian M. nivale isolates from cereals and grasses support the assumption that host specialization exist within M. nivale isolates.
Abstract
There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the perennial weed flora. The effect of mechanical weeding and fertilisation on perennial weeds, fungal diseases and soil structure were evaluated in two different experiments in spring cereals. Experiment I included six strategies. The first strategy was (1) without specific measures against perennial weeds. The other strategies encompassed one or two seasonal control measures; (2) rhizome/root cutting with minimal soil disturbance in autumn, (3) hoeing with 24 cm row spacing, (4) combined hoeing and disc harrowing in autumn, (5) ‘KvikUp’ harrowing in spring, and (6) ‘KvikUp’ harrowing in spring and autumn. Experiment II included factor (i) inter-row hoeing and (ii) fertilisation level. This experiment included the comparison between normal row spacing (12 cm) with weed harrowing versus double row spacing (=24 cm) in combination with inter-row hoeing and 4 fertilisation levels (50–200 kg N ha−1). In experiment I the strategies consisting of no or one direct weed control measure (1, 2, 3 and 5) clearly did not control the perennial weeds. The two seasonal control measures (4 and 6) gave a satisfactory weed control and highest crop yield. The combination of best weed control and no measured harmful effects on soil structure or increase of fungal diseases may explain the highest yields for these strategies. In Experiment II, hoeing and 24 cm spacing gave less perennial biomass compared to 12 cm spacing. Grain yields increased linearly with increasing nitrogen input. The study shows that both inter-row hoeing and weed harrows, are important elements in integrated pest management practice and organic farming. In addition, our results indicate that efficient mechanical weeding is possible without harmful effects in crop rotation consisting of various spring cereals as regards soil structure and plant health.
Authors
Christer Magnusson Ari Hietala Per Hansen Eva Solbjørg Flo Heggem Irene Rasmussen Birgit Schaller Marte Persdatter Tangvik Ben Z HellalAbstract
I 2019 års kartlegging av furuvednematoden Bursaphelenchus xylophilus i Norge ble 400 prøver tatt fra hogstavfall og vindfall av Pinus sylvestris L. med angrep av furubukk Monochamus spp. Prøvene ble tatt ut i Akershus, Buskerud, Østfold, Telemark, Aust-Agder og Vest-Agder. Prøvene som besto av flis ble inkubert ved +25oC i to uker før de ble ekstrahert med Baermanntrakt og undersøkt i mikroskop. Furuvednematoden B. xylophilus ble ikke påvist i prøvene, men den naturlig forekommende arten Bursaphelenchus mucronatus kolymensis ble oppdaget i fire prøver fra Agderfylkene. Feller med feromoner for fangst av furubukk ble satt opp i Hedmark (Elverum, Romedal, Stange og ved Geitholmsjøen), Møre og Romsdal (Kvanne) og Østfold (Fredrikstad og Vestby). I laboratoriet ble billene kuttet i biter og ekstrahert med en modifisert Baermanntrakt. Suspensjonen fra ekstraksjonene ble undersøkt i stereomikroskop for forekomst av infektive stadier av Bursaphelenchus spp.. Ingen nematoder kunne påvises i de 106 undersøkte billene. I perioden 2000 – 2019 er totalt 8123 vedprøver analysert. Flest prøver er tatt i Østfold, fulgt av Hedmark, Telemark, Buskerud og Aust-Agder. I kartleggingen 2019 ble B. mucronatus kolymensis påvist i fire av de 400 vedprøvene, tilsvarende en frekvens på 0,01 (1 %). For hele perioden 2000 - 2019 ble Bursaphelenchus mucronatus kolymensis + B. macromucronatus, oppdaget i 73 av 8123 vedprøver som gir en eteksjonsfrekvens på 0,009 (ca. 1 %). I perioden 2014-2019 har Bursaphelenchus mucronatus kolymensis blitt påvist fem av totalt 581 biller, som gir den samme frekvensen som for vedprøver. B. mucronatus kolymensis og B. macromucronatus likner på B. xylophilus i generell biologi og habitatvalg. Hvis vi antar en hypotetisk frekvens i forekomsten til B. xylophilus som er 100 ganger lavere enn for disse naturlig forekommende nematodene, dvs. 0,00009, kan det antall prøver som trengs for en påvisning av B. xylophilus med 95 % konfidensintervall estimeres til 30 801. Dette indikerer at vi i dag hypotetisk sett har nådd bare 26 % av det antall prøver som trengs for å kunne erklære Norge fri for furuvednematoden B. xylophilus.
Authors
Melissa Magerøy Erik Christiansen Bo Långström Anna-Karin Borg-Karlson Halvor Solheim Niklas Björklund Tao Zhao Axel Schmidt Carl Gunnar Fossdal Paal KrokeneAbstract
Plants can form an immunological memory known as defense priming, whereby exposure to a priming stimulus enables quicker or stronger response to subsequent attack by pests and pathogens. Such priming of inducible defenses provides increased protection and reduces allocation costs of defense. Defense priming has been widely studied for short‐lived model plants such as Arabidopsis, but little is known about this phenomenon in long‐lived plants like spruce. We compared the effects of pretreatment with sublethal fungal inoculations or application of the phytohormone methyl jasmonate (MeJA) on the resistance of 48‐year‐old Norway spruce (Picea abies) trees to mass attack by a tree‐killing bark beetle beginning 35 days later. Bark beetles heavily infested and killed untreated trees but largely avoided fungus‐inoculated trees and MeJA‐treated trees. Quantification of defensive terpenes at the time of bark beetle attack showed fungal inoculation induced 91‐fold higher terpene concentrations compared with untreated trees, whereas application of MeJA did not significantly increase terpenes. These results indicate that resistance in fungus‐inoculated trees is a result of direct induction of defenses, whereas resistance in MeJA‐treated trees is due to defense priming. This work extends our knowledge of defense priming from model plants to an ecologically important tree species.