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.
2018
Abstract
Olfaction is the most important sensory mechanism by which many insects interact with their environment and a wind tunnel is an excellent tool to study insect chemical ecology. Insects can locate point sources in a three-dimensional environment through the sensory interaction and sophisticated behavior. The quantification of this behavior is a key element in the development of new tools for pest control and decision support. A wind tunnel with a suitable flight section with laminar air flow, visual cues for in-flight feedback and a variety of options for the application of odors can be used to measure complex behaviour which subsequently may allow the identification of attractive or repellent odors, insect flight characteristics, visual-odor interactions and interactions between attractants and odors lingering as background odors in the environment. A wind tunnel holds the advantage of studying the odor mediated behavioural repertoire of an insect in a laboratory setting. Behavioural measures in a controlled setting provide the link between the insect physiology and field application. A wind tunnel must be a flexible tool and should easily support the changes to setup and hardware to fit different research questions. The major disadvantage to the wind tunnel setup described here, is the clean odor background which necessitates special attention when developing a synthetic volatile blend for field application.
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1 The European spruce bark beetle Ips typographus is a damaging pest on spruce in Europe. Beetle interactions with tree species originating outside the natural range of the beetle are largely unknown and may be unpredictable because trees without a co-evolutionary history with the beetle may lack effective defences. 2 The terpenoid composition and breeding suitability for I. typographus of the historic host Norway spruce Picea abies were compared with two evolutionary naïve spruces of North American origin that are extensively planted in North-West Europe: Sitka spruce Picea sitchensis and Lutz spruce Picea glauca x lutzii. 3 The bark of all three species had a similar chemical composition and similar levels of total constitutive terpenoids, although Norway spruce had higher total induced terpenoid levels. 4 Beetles tunnelling in the three spruce species produced similar amounts of aggregation pheromone. Controlled breeding experiments showed that I. typographus could produce offspring in all three species, with a similar offspring length and weight across species. However, total offspring production was much lower in Sitka and Lutz spruce. 5 Overall, the results of the present study suggest that I. typographus will be able to colonize Sitka and Lutz spruce in European plantations and in native spruce forests in North America if introduced there.
Authors
Heidi Udnes Aamot Ingeborg Klingen Simon Edwards May Bente Brurberg Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardAbstract
The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in crop residues, weeds, and soil sampled from a selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. The different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence of F. langsethiae in oat. Results show that F. langsethiae DNA may occur in the oat plant already before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. No Fusarium DNA was detected in soil samples. Of the arthropods that were associated with the collected oat plants, aphids and thrips species were dominating. Further details will be given at the meeting.
2017
Authors
Bjørn Arild Hatteland Elena Therese Wulf-Vester Ida Gundersen Nuria Agusti Lene Sigsgaard Nina TrandemAbstract
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Abstract
Creeping perennial weeds are of major concern in organically grown cereals. In the present study, the effects of different timing of mouldboard ploughing with or without a preceding stubble cultivation period, on weeds and spring cereals were studied. The experiments were conducted at two sites in Norway during a two and three-year period, respectively, with the treatments repeated on the same plots. The soil cultivation treatments were a stubble disc-harrowing cultivation period followed by mouldboard ploughing and only mouldboard ploughing. The timing of the treatments were autumn or spring. The density and biomass of the aboveground shoots of Cirsium arvense (L.) Scop., Elymus repens (L.) Gould, Sonchus arvensis L. and Stachys palustris L. as well as the total aboveground biomass of the spring cereal crop (oats) were assessed. The control efficiency of C. arvense and S. arvensis was closely related to timing of the cultivation treatments. Cultivation in spring decreased the population of C. arvense and S. arvensis compared to autumn cultivation. For E. repens, timing of the treatments had no significant effect: the important factor was whether stubble cultivation was carried out (best control) or not. The overall best strategy for controlling the present perennial weed population was stubble cultivation followed by ploughing in spring. However, the associated relative late sowing of the spring cereal crop and lowered crop biomass, were important drawbacks.
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Authors
Nina Trandem Upendra Raj Bhattarai Isabelle Bueno Silva Karin Westrum Geir Kjølberg Knudsen Ingeborg KlingenAbstract
No abstract has been registered