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.
2024
Authors
Ritter Atoundem Guimapi Berit Nordskog Anne-Grete Roer Hjelkrem Ingeborg Klingen Ghislain Tchoromi Tepa-Yotto Manuele Tamò Karl ThunesAbstract
The fall armyworm, Spodoptera frugiperda, situation in Africa remains a priority threat despite significant efforts made since the first outbreaks in 2016 to control the pest and thereby reduce yield losses. Field surveys in Benin and Mali reported that approximately one-week post-emergence of maize plants, the presence of fall armyworm (egg/neonates) could be observed in the field. Scouting for fall armyworm eggs and neonates is, however, difficult and time consuming. In this study, we therefore hypothesized that the optimum timeframe for the fall armyworm female arriving to lay eggs in sown maize fields could be predicted. We did this by back-calculating from interval censored data of egg and neonates collected in emerging maize seedlings at young leaf developmental stage. Early time of ovipositing fall armyworm after sowing was recorded in field experiments. By using temperature-based models to predict phenological development for maize and fall armyworm, combined with analytical approaches for time-to-event data with censored status, we estimated that about 210 accumulated Degree Days (DD) is needed for early detection of neonate larvae in the field. This work is meant to provide new insights on timely pest detection and to guide for precise timing of control measures.
Abstract
No abstract has been registered
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No abstract has been registered
Authors
Ari Hietala Wilson Lara Henao André Kolsgaard Simon Seljegard Nina Elisabeth Nagy Isabella Børja Tor Arne Justad Yngve Rekdal Even Bergseng Halvor SolheimAbstract
Forest grazing by free-roaming livestock is a common practice in many countries. The forestry sector sees the practice as unfortunate owing to several reasons, such as damages inflicted by grazing in young plantations. Concerning Norway spruce forests, a tree species known to develop wood decay with high frequency followed from stem bark damage, there is a strong perception among foresters that the trampling damage caused by livestock on the superficial root system of this tree leads to decay. Because of the very limited scientific documentation available on this topic, we pursued a clarification by investigating three 38- to 56-year-old Norway spruce forests used for silvopasture. Two types of injuries were observed on exposed roots: bark cracks characterized by resin exudation, and injuries involving localized bark peeling and exposure of the underlying wood. These injuries occurred up to 250 cm away from the root collar, with the sector 50–150 cm away from the root collar showing the highest incidence of injuries. In two of the forest stands, wood within the injured root areas was primarily colonized by the wound parasite Corinectria fuckeliana or species of the order Helotiales, fungi that do not cause wood decay. Wood colonization of injured roots by Heterobasidion species, the most frequent wood decay fungi of Norway spruce, was common in the third stand, but only in a few cases it was possible to deduce that the colonization had probably initiated via trampling injuries on roots. In a few cases, an injury was located at stem base at the root collar height along paths used by animals, and in such cases, it was obvious that stem colonization by Heterobasidion species had initiated via the wound. The relatively small amount of data warrants caution when drawing conclusions. Considering the high establishment frequency of decay via stem bark wounds of Norway spruce observed in previous studies, our data would suggest that roots are generally better equipped to defend themselves upon infliction of superficial wounds than stem of this tree species. The likelihood of trampling injuries leading to decay may vary considerably between different stands, this presumably depending on the level of local propagule pressure by pathogenic wood decay fungi and the frequency of damages close to root collar.
Authors
Carl Gunnar Fossdal Paal Krokene Jorunn Elisabeth Olsen George Richard Strimbeck Marcos Viejo Igor A. Yakovlev Melissa MagerøyAbstract
Gymnosperms are long-lived, cone-bearing seed plants that include some of the most ancient extant plant species. These relict land plants have evolved to survive in habitats marked by chronic or episodic stress. Their ability to thrive in these environments is partly due to their phenotypic flexibility, and epigenetic regulation likely plays a crucial part in this plasticity. We review the current knowledge on abiotic and biotic stress memory in gymnosperms and the possible epigenetic mechanisms underlying long-term phenotypic adaptations. We also discuss recent technological improvements and new experimental possibilities that likely will advance our understanding of epigenetic regulation in these ancient and hard-to-study plants.
Abstract
No abstract has been registered
Authors
Jorunn Børve Theresa Weigl Emily Follett Ingunn Øvsthus Hanne Larsen Torbjørn Haukås Erlend Indergård Siv Fagertun Remberg Dalphy Ondine Camira Harteveld Arne StensvandAbstract
No abstract has been registered
Authors
Paal Krokene Beatrix Alsanius Jorunn Børve Daniel Flø Bjørn Arild Hatteland Erik J. Joner Lawrence Richard Kirkendall Christer Magnusson Mogens Nicolaisen Line Nybakken Johan Stenberg Selamawit Tekle Gobena Kristine Bakke Westergaard Sandra A. I. WrightAbstract
Background: The Norwegian Environment Agency (Miljødirektoratet) and the Norwegian Food Safety Authority (Mattilsynet) tasked the Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) to provide a scientific opinion identifying which growing media associated with import of live plants pose the greatest risk of introducing non-native species to Norway. VKM was also asked to assess how effective various risk-reducing measures are to prevent such introductions. In this report, we focus on the introduction of plant pests. Trade in plants for planting is a large and complex international business where live plants are grown in some areas and shipped to other areas where they are intended to be planted or replanted. Traded plants are usually shipped with associated growing media. Long-lived plants, like trees and bushes, may be imported to the EU (e.g., from Asia) and traded through different countries for several years of on-growth before being shipped to Norway. Long production cycles, partly in outdoor nurseries, suggest that the import of live plants with soil or other growing media into Norway comes with a high probability of introducing plant pests. Such pests could cause severe harm to Norwegian plant health and impact both agriculture and natural ecosystems. In this scientific opinion, we describe the most used growing media and assess the risks associated with these. We further evaluate what types of plants and which exporting countries are considered to pose the highest risks for introducing plant pests. Finally, we describe different risk reduction options and assess the effectiveness of current Norwegian regulations as a tool to reduce risks. Altogether, this assessment provides a comprehensive overview of the potential risks involved in importing soil and other growing media associated with plants for planting and of possible strategies for mitigating these risks. Key findings: Growing media constituents: The most used organic growing media constituents are peat, wood fiber, and compost, but a great array of other constituents is also used. In this report, we have focused on organic constituents, as these are frequently colonized by living organisms when sourced and may support pest species by acting as a food source or as a sheltering environment that provides water, oxygen, and other crucial factors for pest survival. Growing media as a plant pest carrier: Even though most growing media constituents initially are sterile or free from any plant pests, the processes of mixing, potting, plant cultivation, transport, and storage can easily allow contamination by and propagation of pests underway from a primary source to a customer in Norway. Many organisms can colonize and survive in growing media under conditions primarily designed to keep plants alive. Growing media thus poses a risk of introducing plant pests to Norway when such media are imported together with live plants. Identified pest species: Organisms that can arrive with the import of live plants and associated growing media will include organisms that are not plant pests, known plant pests, regulated pests, and species that may be problematic even though they are not currently listed as quarantine pests. By screening two international databases (CABI, 2022; EPPO, 2024b) and performing a structured literature search, we identified a total of 651 pest species, most of which are not present in Norway, that may be associated with plants imported from Europe with soil or other growing media (154 species from CABI, 87 from EPPO, and 410 from the literature search). Due to time limitations, only 89 species were assessed for their association with soil and growing media. This evaluation included 20 species from CABI, 24 from EPPO, and 45 from the literature search, as detailed in Appendix 5. Climate suitability analyses were carried out .........
Authors
Ngan Bao Huynh Paal Krokene Jorunn Elisabeth Olsen Taina Pennanen Adriana Puentes Vaida Sirgedaitė-Šėžienė Vytautas Čėsna Ieva Čėsnienė Melissa MagerøyAbstract
No abstract has been registered
Abstract
• For more than 20 years, methyl jasmonate (MeJA) has been used to study inducible defenses in conifers and to increase tree resistance to pests and pathogens. Despite the numerous studies on the subject, no attempts have been made to summarize or quantify how MeJA affects resistance and growth in conifers. Here we present a quantitative meta-analysis of the effects of MeJA treatment on the conifer genera Pinus and Picea, two of the most economically and ecologically important tree genera in boreal, temperate, and alpine forests. • A literature search yielded 120 relevant papers. We summarized the key experimental methods used in these papers and performed a meta-analysis of how MeJA affects tree growth and resistance to pests and pathogens. • The results show that MeJA negatively affects tree growth, with an overall effect size of −0.63. The overall effect size of MeJA for tree resistance was −0.76, indicating that MeJA treatment significantly reduces tree damage caused by biotic stressors. • Although our meta-analysis shows that MeJA is effective in enhancing conifer defenses, there are still gaps in our understanding of the durability and ecological consequences of MeJA treatment. We provide suggestions for how future research should be conducted to address these gaps.