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.
2016
Forfattere
Marte Holten Jørgensen Abdelhameed Elameen Nadine Hofman Sonja Klemsdal Sandra Malaval Siri FjellheimSammendrag
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Sammendrag
The apple fruit moth (Argyresthia conjugella (A. conjugella)) in Norway was first identified as a pest in apple production in 1899. We here report the first genetic analysis of A. conjugella using molecular markers. Amplified fragment length polymorphism (AFLP) analysis was applied to 95 individuals from six different locations in the two most important apple-growing regions of Norway. Five AFLP primer combinations gave 410 clear polymorphic bands that distinguished all the individuals. Further genetic analysis using the Dice coefficient, Principal Coordinate analysis (PCO) and Bayesian analyses suggested clustering of the individuals into two main groups showing substantial genetic distance. Analysis of molecular variance (AMOVA) revealed greater variation among populations (77.94%) than within populations (22.06%) and significant and high FST values were determined between the two major regions (Distance = 230 km, FST = 0.780). AFLP analysis revealed low to moderate genetic diversity in our population sample from Norway (Average: 0.31 expected heterozygosity). The positive significant correlation between the geographic and the molecular data (r2 = 0.6700) indicate that genetic differences between the two major regions may be due to geographical barriers such as high mountain plateaus (Hardangervidda) in addition to isolation by distance (IBD).
Forfattere
T. Jung L. Orlikowski B. Henricot P. Abad-Campos A.G. Aday O. Aguín Casal J. Bakonyi S.O. Cacciola T. Cech D. Chavarriaga T. Corcobado A. Cravador T. Decourcelle G. Denton S. Diamandis H.T. Doğmuş-Lehtijärvi A. Franceschini B. Ginetti M. Glavendekić J. Hantula G. Hartmann Maria Herrero D. Ivic M. Horta Jung A. Lilja N. Keca V. Kramarets A. Lyubenova H. Machado G. Magnano di San Lio P.J. Mansilla Vázquez B. Marçais I. Matsiakh I. Milenkovic S. Moricca Z.Á. Nagy J. Nechwatal C. Olsson T. Oszako A. Pane E.J. Paplomatas C. Pintos Varela S. Prospero C. Rial Martínez D. Rigling C. Robin A. Rytkönen M.E. Sánchez B. Scanu A. Schlenzig J. Schumacher S. Slavov A. Solla E. Sousa J. Stenlid Venche Talgø Z. Tomic P. Tsopelas A. Vannini A. M. Vettraino M. Wenneker S. Woodward A. Perez-SierraSammendrag
Det er ikke registrert sammendrag
Forfattere
Venche Talgø Jan-Ole Skage Arne Steffenrem Corina Junker Håvard Eikemo May Bente Brurberg Odd Ragnar JohnskåsSammendrag
Delphinella shoot blight (Delphinella abietis) attacks true firs (Abies spp.) in Europe and North America. Especially subalpine fir (A. lasiocarpa), one of the main Christmas tree species in Norway, is prone to the disease. The fungus kills current year needles, and in severe cases entire shoots. Dead needles become covered with black fruiting bodies, both pycnidia and pseudothecia. Delphinella shoot blight has mainly been a problem in humid, coastal regions in the northwestern part of Southern Norway, but, probably due to higher precipitation in inland regions during recent years, heavy attacks were found in 2011 in a field trial with 76 provenances of subalpine fir in Southeastern Norway. However, the amount of precipitation seemed less important once the disease had established in the field. Significant differences in susceptibility between provenances were observed. In general, the more bluish the foliage was, the healthier the trees appeared. The analysis of provenance means indicated that, at least for the southern range, the disease ratings were correlated with foliage color. This study also includes isolation, identification, a pathogenicity test, a seed test and electron microscopy of the wax layer on the needles. The fungus was identified based on the morphology of spores and by sequencing the Internal Transcribed Spacer (ITS) regions of the ribosomal DNA. Koch’s postulates were fulfilled. The fungus was found present on newly harvested seeds and may therefore spread via international seed trade. When comparing the wax layers on green and blue needles, those of the latter were significantly thicker, a factor that may be involved in disease resistance.
Forfattere
Anita Nussbaumer Peter Waldner Sophia Etzold Arthur Gessler Sue Benham Iben Margrete Thomsen Bruno Bilde Jørgensen Volkmar Timmermann Arne Verstraeten Geert Sioen Pasi Rautio Liisa Ukonmaanaho Mitja Skudnik Vladislav Apuhtin Sabine Braun Alexandra WauerSammendrag
Det er ikke registrert sammendrag
Forfattere
Isabella Børja Jan Svetlik Valeriy Nadezhdin Jan Čermák Sabine Rosner Nadezhda NadezhdinaSammendrag
Top dieback of Norway spruce (Picea abies), triggered by drought in 2004–2006, has been observed in Southeast Norway and trees died within four years after appearance of the first symptoms. The aim of our study was to use sap flux measurements as a diagnostic method for assessment of tree vitality. We used the heat field deformation method to monitor the sap flux density (SFD) in four pairs of healthy and declining trees in situ. To provide retrospective information on hydraulic performance of the trees we took samples for wood anatomical analysis. After felling the trees we used the modified differential translucence method (MDT) as a proxy for the SFD measurements. Healthy trees had three times higher SFD values as declining trees. In some healthy trees we detected decreasing SFD with time. The MDT method agreed with the SFD measurements. In conclusion, we detected sap flux dysfunction in declining trees and showed that the SFD reduction may occur during a short period, prior to occurrence of any visual symptoms. We suggest incorporating the SFD measurements into the repertoire of diagnostic tools in forest pathology.
Sammendrag
The purpose of this study is to increase the basic understanding of outbreak dynamics in order to improve the management of bark beetle outbreaks. The spruce bark beetle Ips typographus is a major disturbance agent of European forests and is the continent’s most economically and environmentally damaging bark beetle. Outbreaks of the spruce bark beetle are often triggered by large windfall episodes, and we have utilized a unique opportunity to study a Slovakian outbreak where little salvage logging was performed in some areas after a 2.5 million m3 storm-felling in 2004. Our analyses focused on the first five years after the windfall, and we used a combination of empirical data and simulation models to understand the spatial patterns of beetle-killed forest patches developing during the outbreak. The univoltine beetle population used an increasing proportion of the windfelled trees during the two first seasons after the storm, but from the third season onwards our comparisons of inter-patch distance distributions indicated a transition from beetle production largely in windfall areas to a self-sustaining outbreak with infestation patches developing independently of the windthrows. The size of new infestation patches formed after this transition was modeled as a function of beetle pressure, estimated by the proportion of a circle area surrounding new patches that was covered by infestation patches the previous year. Our model results of patch size distribution did not correspond well with the empirical data if patch formation was modeled as a pure dispersal–diffusion process. However, beetle aggregation on individual trees appears to be important for patch development, since good correspondence with empirical data was found when beetle aggregation was incorporated in the modeled dispersal process. The strength of correspondence between the beetle aggregation model and the empirical data varied with the density of aggregation trees in the modeled landscape, and reached a maximum of 83% for a density of three aggregation trees per infestation patch. Our results suggest that efficient removal of windfelled trees up until the start of the second summer after a major windfall is important to avoid a transition into a patch-driven bark beetle outbreak that is very difficult to manage. Our results also indicate that the outcome of a patch-driven outbreak is difficult to predict, since the development of new infestation patches is not a simple function of beetle pressure but is also affected by beetle behavior and local forest conditions.
Sammendrag
This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg−1 in two sets of samples: one with and one without clean-up. For both spiking levels, 80–82% of the pesticides in the non-cleaned extracts and 80–84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70–120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93–95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailed t-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of −20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up.
Sammendrag
A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.
Sammendrag
Det er ikke registrert sammendrag