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.
2012
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Camilla Østerud M. Ashraful Islam Jorunn Elisabeth Olsen Dag-Ragnar Blystad Sissel Torre Anne Kathrine Hvoslef-Eide Jihong Liu ClarkeAbstract
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Abdelhameed Elameen DenisTourvieille de Labrouhe Emmanuelle Mestries Sonja Klemsdal Sophia AhmedAbstract
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Trygve S. Aamlid Siri Fjellheim Abdelhameed Elameen Sonja Klemsdal Kristin Daugstad Hans Martin Hanslin Knut Hovstad Dagmar Hagen Knut Rydgren Line RosefAbstract
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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.
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Authors
Sheng-Hong Li Nina Elisabeth Nagy Almuth Hammerbacher Paal Krokene Xue-Mei Niu Jonathan Gershenzon Bernd SchneiderAbstract
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.