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.
2019
Authors
Tao Zhao Suresh Ganji Christian Schiebe Björn Bohman Philip Weinstein Paal Krokene Anna-Karin Borg-Karlson C. Rikard UneliusAbstract
Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles. Volatile emissions of five common bark beetle symbionts were investigated by gas chromatography-mass spectrometry. When grown on fresh Norway spruce bark the fungi emitted three well-known bark beetle aggregation pheromones and semiochemicals (exo-brevicomin, endo-brevicomin and trans-conophthorin) and two structurally related semiochemical candidates (exo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane and endo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane) that elicited electroantennogram responses in the spruce bark beetle Ips typographus. When grown on malt agar with 13C D-Glucose, the fungus Grosmannia europhioides incorporated 13C into exo-brevicomin and trans-conophthorin. The enantiomeric compositions of the fungus-produced ketals closely matched those previously reported from bark beetles. The production of structurally complex bark beetle pheromones by symbiotic fungi indicates cross-kingdom convergent evolution of signal use in this system. This signaling is susceptible to disruption, providing potential new targets for pest control in conifer forests and plantations.
Authors
Tomáš Hlásny Rupert Seidl Kenneth F Raffa Jörg Müller Claire Montagné-Huck Andrew M. Liebhold Hua Qin Mart-Jan Schelhaas Paal Krokene Miroslav Svoboda Heli ViiriAbstract
No abstract has been registered
Authors
Tomáš Hlásny Paal Krokene Andrew Liebhold Claire Montagné-Huck Jörg Müller Hua Qin Kenneth F Raffa Mart-Jan Schelhaas Rupert Seidl Miroslav Svoboda Heli ViiriAbstract
No abstract has been registered
Authors
Paal KrokeneAbstract
No abstract has been registered
Authors
Anna Maria Vettraino Alberto Santini Christo Nikolov Jean-Claude Grégoire Rumen Tomov Andrei Orlinski Tiit Maaten Halldor Sverrisson Bjørn Økland René EschenAbstract
Sentinel plants, plants in exporting countries that are inspected at regular intervals for signs and symptoms of invertebrate pests and microbial pathogens, are a promising tool for detecting and identifying harmful organisms of woody plants prior to their introduction into importing countries. Monitoring of sentinel plants reveals crucial information for pest risk analyses and the development of mitigation measures. The establishment of sentinel plants requires the import and plantation of non-native plants, which may be affected by the laws, regulations and administrative procedures in the individual countries. To evaluate the feasibility of sentinel plants as a global approach, this study aimed to summarise regulations and administrative procedures that affect the establishment of sentinel plants using non-native plants in countries worldwide. Information about national regulations of import and planting of non-native plant species was collected through a questionnaire survey, conducted among national representatives to the International Plant Protection Convention. Over 40 countries responded. The results show that legislations and regulations should not be major obstacles for a global use of the sentinel plants approach. However, the few existing experiences show that it can be complicated in practice. Here we describe the current state of art of the procedures that should be adopted to establish sentinel plants and we propose a strategy to circumvent the shortcomings resulting from the lack of a specific regulation.
Authors
Bjørn ØklandAbstract
The populations sizes of Ips typographus in Norway have been monitored since the last big outbreak period in the 1970s. By now the monitoring programme includes about 500 pheromone-baited trap records for each of the last 40 years. Normally, Ips typographus has been the only species of major concern in northern bark beetle outbreaks, and trapping records have served as a warning when the over-wintering population sizes are large. In contrast to Central Europe, the regional trend in northwest is that rainy weather tend to slow down the bark beetle populations in many years, whereas stormfelling episodes of spruces, snowbreaks and warm and dry seasons in certain years favour Ips typographus and other bark beetle species. Recent observations indicate that other less aggressive bark beetle species may play a more important role during severe drought periods that follow rainful seasons with low production of Ips typographus. It is likely that an increased frequency of extreme weather events may have unexpected effects on what bark beetles become abundant during the course of the outbreaks. Furthermore, the warm years seem to be especially favourable for the Ips typographus at the northernmost latitudes. In addition, a new bark beetle species for Scandinavia, Ips amitinus, is expanding its range and may become a participant in future bark beetle outbreaks in this region.
Authors
Bjørn Økland Daniel Flø Martin Schroeder Peter Zach Dragos Cocos Petri Martikainen Juha Siitonen Michail Y. Mandelshtam Dmitry L. Musolin Seppo Neuvonen Jozef Vakula Christo Nikolov Åke Lindelöw Kaljo VoolmaAbstract
1 Ips amitinus arrived in Northern Europe at the beginning of 1900s, although its recent expansions to the northernmost conifers have been rapid. 2 Analyses of recent records, MaxEnt models and regional population size estimates are used to discuss its peculiar range shifts and potential as a forest pest in Northern Europe. 3 Ips amitinus was probably absent in northern glacial refugia for Norway spruce in the Russian plain and northward expansions from its glacial refugia in the Central European mountains may have been slowed down by: (i) ecological barriers of post-glacial dry plains and bogs in Central Europe; (ii) heavy utilization of conifers; and (iii) Allee effects as a result of fragmented forests and an unfavourable climate for a cold-adapted species in the continental lowlands. 4 MaxEnt models predict that I. amitinus may become widespread in the Northern European forests, whereas its populations in the southernmost mountain ranges of Europe may decline in the future. 5 The population levels of I. amitinus in recently invaded northern areas are still lower than those in core areas of Central Europe, although the population development in Central Europe indicates that future bark beetle outbreak periods may boost the I. amitinus populations in Northern Europe as well.
Authors
Jorunn BørveAbstract
No abstract has been registered
Abstract
The positive effect of low oxygen and high CO2 for sweet cherry (Prunus avium L.) storability is well-known. In the present experiment, a combination of controlled atmosphere (CA; 2°C, 5% O2 and 15% CO2) storage and modified atmosphere in consumer packaging (MAP) were assessed. Fruit of 'Kordia' were packaged directly (0-week CA) or after three weeks in CA storage (3-week CA). The different packages were 1: macro-perforated polyethylene bag (carry bags); 2: trays wrapped in perforated films giving passive modified atmosphere with high CO2 concentration (MAP-high CO2); 3: similar as 2, but with low CO2 concentration (MAP-low CO2); 4: perforated shaker with lid containing cherries with stem; and 5: similar as 4, but with fruit without stems. The consumer packages were stored at 4°C for 5 days and thereafter for 3 days at 4°C (Chill) or 20°C (Retail) simulating different retail storage conditions. The weight loss was below 1% for fruit in all packages stored at chill conditions. At retail conditions, weight loss for cherries in carry bags varied between 2.2 and 8.4%, whereas MA packages had insignificant weight loss. Fungal fruit decay was below 0.5% for 0-week CA cherries stored at chill conditions for 8 days, and from 7 to 14% for 3-week CA cherries stored at chill conditions for 6 days after packaging. At retail conditions, 25 to 52% decay was detected at end of storage period after previous storage in 0 and 3 weeks in CA, respectively. Sweet cherries of 'Kordia' did not maintain an acceptable quality in 3 weeks of CA with consecutive simulated distribution conditions during 6 days. Fungal decay was lower in carry bags and MA packaging with high CO2, and the MA packages had additionally insignificant weight loss in mean of the different temperature regimes and storage times.
Abstract
No abstract has been registered