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.
2012
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Kirsten Tørresen Ingerd Skow Hofgaard Jan Netland Lars Olav Brandsæter Guro Brodal Oleif Elen Andrea Ficke Marit Almvik Randi Bolli Marianne Stenrød Einar StrandSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
The pea moth Cydia nigricana (Lepidoptera: Tortricidae) is the key pest of the pea Pisum sativum (Fabaceae). Alternative pest control techniques need to be developed since efficient control options are scarce. Field studies in Northern Hessen, Germany, in the years 2006 - 2008 demonstrated a strong correlation between the seasonal flight period of C. nigricana and the phenology of pea. With this starting point, we propose to study the olfactory space between the pea plant and the pea moth, aiming to identify volatile cues encoding host recognition and host finding in pea moth females, and the potential use of these compounds for control of the pea moth. As a first step, two-choice experiments in the laboratory concerning complex plant odours were conducted to study the preference between different phenological development stages of pea plants using male and female C. nigricana (mated and non-mated). Males and non-mated females showed no preference, whereas mated females clearly preferred flowering pea plants. To study the host finding behaviour and upwind orientation of C. nigricana we conducted wind tunnel experiments, using pea plants in different phenological development stages. The preference of mated females for the pea flower has been confirmed and additionally, high attraction of mated females for the late bud stage was recorded. Overall, the flower and the late bud stage of P. sativum seem to be the most important phenological development stage of pea for host finding behaviour of C. nigricana. The next steps in this study are the identification, selection and characterisation of behavioural active pea plant compounds.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Sheng-Hong Li Nina Elisabeth Nagy Almuth Hammerbacher Paal Krokene Xue-Mei Niu Jonathan Gershenzon Bernd SchneiderSammendrag
Norway spruce (Picea abies) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle Ips typographus and its microbial associate, the blue stain fungus Ceratocystis polonica. These cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. Laser microdissection of spruce bark sections combined with cryogenic NMR spectroscopy demonstrated significantly higher concentrations of the stilbene glucoside astringin in phloem parenchyma cells than in adjacent sieve cells. After infection by C. polonica, the flavonoid (+)-catechin also appeared in phloem parenchyma cells and there was a decrease in astringin content compared to cells from uninfected trees. Analysis of whole-bark extracts confirmed the results obtained from the cell extracts and revealed a significant increase in dimeric stilbene glucosides, both astringin and isorhapontin derivatives (piceasides A to H), in fungus-infected versus uninfected bark that might explain the reduction in stilbene monomers. Phloem parenchyma cells thus appear to be a principal site of phenolic accumulation in spruce bark.
Sammendrag
The aim of this paper is to complete the studies of the genus Stenostola in Northern Europe. Together with previous published studies the characters presented form a better basis for separation of S. ferrea and S. dubia both as imagines and as larvae. The presented paper consists of three parts: Studies of the genitalia, morphological characters for identification of the larvae and DNA barcoding of both Stenostola dubia (Laicharting, 1784) and S. ferrea (Shrank, 1776). Although very similar, the male genitalia have good characters for species separation. The easiest characters to use are the parameres and tips of sclerite 2. The posterior ends of the elongated median sclerites of S. ferrea are irregularly curved or “zigzag” shaped, while the posterior ends of the median sclerites of S. dubia are straight. The genitalia characters presented are not previously published. No single morphological character alone is enough to identify the larvae to species. However, when the characters are used together the mature larvae are usually identifiable. The younger the larvae are, the more difficult they are to identify. Barcoding analysis of mitochondrial COI gene shows that S. ferrea and S. dubia are genetically different. The genetic distance between the species is 10.3 %. These results, in addition to previous findings, show that despite the morphological similarities, they are clearly two different species.
Forfattere
Aruppillai Suthaparan Arne Stensvand Knut Asbjørn Solhaug Sissel Torre Leiv M. Mortensen David M. Gadoury R.C. Seem Hans Ragnar GislerødSammendrag
Det er ikke registrert sammendrag
Sammendrag
Ceratocystis polonica and Heterobasidion parviporum are important fungal pathogens in Norway spruce (Picea abies). Tree susceptibility to these pathogens with respect to phenology was studied using artificial fungal inoculations at six stages of bud development, and assessed by measuring phloem necroses in the stems of 2- and 8-year-old trees. Tree capacity for resistance was assessed by measuring phloem nonstructural carbohydrates at each stage. Phloem necroses were significantly larger in trees with fungal versus control inoculations and increased significantly over time. Changes in nonstructural carbohydrates occurred in the trees; a significant decline in starch and a slight but significant increase in total sugars occurred over time. These results suggest that susceptibility to fungal pathogens and carbohydrate levels in the stems of the trees were related to fine-scale changes in bud development. A trade-off may occur between allocation of starch (the major fraction of the stem carbohydrate pool) to bud development/shoot growth versus defence of the stem. Previous tests of plant defence hypotheses have focused on herbivory on plants growing under different environmental conditions, but the role of phenology and the effect of pathogens are also important to consider in understanding plant resource allocation patterns.
Sammendrag
Increasing inter-continental trade of wood chips for biofuel represents a significant risk of introducing invasive pest species that can cause biome-scale impacts on forest ecosystems. Some potentially invasive species have the capacity to cause high tree mortality on the Eurasian continent and could cause significant impacts on biodiversity and ecosystem functions. Because eradication of established species is difficult, there is a need for scientific studies that can evaluate the reliability of current import control practices to ensure lowest possible risk of establishment of potentially harmful species. We used a stochastic simulation model and sensitivity analyses to evaluate the chance of detecting harmful pests in imported wood chips by sampling according to the current use of internationally accepted standards. As an example, we focused on the North American beetle Agrilus anxius (bronze birch borer) that can cause 100% mortality of European and Asian birch species in North America. We simulated the process from logging in North America to sampling the wood chips upon arrival in Europe. The probability of pest detection for current sampling protocols used by port inspectors was very low (<0.00005), while a 90% chance of detection may require sampling 27 million litres of wood chips per shipload.