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.
2022
Sammendrag
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Sammendrag
Weed-free zone underneath apple trees is important to maximize vegetative growth, fruit yield- and quality. Glyphosate applied twice is the usual strategy in apple orchards in Norway. Due to uncertain future of glyphosate there is a need for alternative strategies. A field trial was conducted during 2021 in an orchard (three-year-old trees). Five alternative strategies were tested: 1) Hot water at 3 L m-2 x 3 (spring, early summer, summer), 2) Hot water at 6 L m-2 x 3 (times as previous), 3) Pelargonic acid at full dose (10.9 kg a.s. ha-1) x 1 (early summer), 4) Pelargonic acid at half dose (5.44 kg a.s. ha-1) x 2 (spring, early summer), and 5) Rotary hoe x 3 (early spring, early summer, summer). Glyphosate at 1.08 kg a.s. ha-1 x 2 (early summer, summer) was included as reference strategy. Hot water (about 80 C, 0.1 bar) was applied with a commercial machine (Heatweed Technologies, Norway). Visual assessments of percentage of ground covered by living vegetation were used to estimate weed control efficacy. Dominating species were Taraxacum officinale, Tripleurospermum inodorum, Poa annua, Polygonum aviculare, Galium aparine, Viola arvensis and Senecio vulgaris. Assessed mid-summer (June 24), hot water applied twice (both 3 L m-2 and 6 L m-2) showed very high efficacies, both about 90%. Pelargonic acid showed rather low efficacies, about 15% (10.9 kg a.s. ha-1 x 1) and 45% (5.44 kg a.s. ha-1 x 2). Rotary hoe twice had almost 60%. Efficacy of glyphosate once was 75%. The last assessment was conducted in mid-July, i.e. about 1-2 weeks after the last application of hot water, rotary hoe and glyphosate. The two hot water strategies resulted in very good weed control, i.e.
Forfattere
Gunnhild Jaastad Nina Trandem Gaute Myren Sigrid Mogan Line Beate Lersveen Endre Bjotveit Irén Lunde Sekse Marianne BøthunSammendrag
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Sammendrag
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Defense priming, the sensitization of inducible defenses, has been extensively studied in annual angiosperms. However, we are just beginning to explore defense priming in woody, long-lived plants. The natural compound methyl jasmonate (MeJA) has been used for over 20 years to study spruce inducible defenses. Recently, it was discovered that MeJA not only directly induces defense, but also primes defense responses in spruce. Metabolite and transcriptional analyses of mature trees treated with MeJA and subsequently wounded showed that while terpenes accumulate at the wound site in a primed manner, terpene biosynthesis genes are directly induced by MeJA. Pathogen resistance (PR) genes, on the other hand, are primed. Sequencing of miRNAs suggests that miRNAs have a regulatory role in MeJA-induced defenses in spruce. Additionally, a detailed transcriptional time course of 2- year-old spruce treated with MeJA indicated that the RNA-directed DNA methylation (RdDM) pathway is involved in the establishment and maintenance of primed defenses. When comparing mechanisms of defense priming in spruce to those in Arabidopsis, it seems that many mechanisms are conserved. However, some aspects, such as jasmonic acid-salicylic acid crosstalk, may be different. Identifying these differences and how they affect forest species is important for practical application of defense priming in forest management.
Forfattere
Sophie Mentzel Merete Grung Roger Holten Knut-Erik Tollefsen Marianne Stenrød S. Jannicke MoeSammendrag
The use of Bayesian networks (BN) for environmental risk assessment has increased in recent years as they offer a more transparent way to characterize risk and evaluate uncertainty than the traditional risk assessment paradigms. In this study, a novel probabilistic approach applying a BN for risk calculation was further developed and explored by linking the calculation a risk quotient to alternative future scenarios. This extended version of the BN model uses predictions from a process-based pesticide exposure model (World Integrated System for Pesticide Exposure - WISPE) in the exposure characterization and toxicity test data in the effect characterization. The probability distributions for exposure and effect are combined into a risk characterization (i.e. the probability distribution of a risk quotient), a common measure of the exceedance of an environmentally safe exposure threshold. The BN model was used to account for variabilities of the predicted pesticide exposure in agricultural streams, and inter-species variability in sensitivity to the pesticide among freshwater species. In Northern Europe, future climate scenarios typically predict increased temperature and precipitation, which can be expected to cause an increase in weed infestations, plant disease and insect pests. Such climate-related changes in pest pressure in turn can give rise to altered agricultural practices, such as increased pesticide application rates, as an adaptation to climate change. The WISPE model was used to link a set of scenarios consisting of two climate models, three pesticide application scenarios and three periods (year ranges), for a case study in South-East Norway. The model was set up for the case study by specifying environmental factors such as soil properties and field slope together with chemical properties of pesticides to predict the pesticide exposure in streams adjacent to the agricultural fields. The model was parameterized and evaluated for five selected pesticides: the three herbicides clopyralid, fluroxypyr-meptyl, and 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), and the two fungicides prothiocanzole and trifloxystrobin. This approach enabled the calculation and visualization of probability distribution of the risk quotients for the future time horizons 2050 and 2085. The risk posed by the pesticides were in general low for this case study, with highest probability of the risk quotient exceeding 1 for the two herbicides fluroxypyr-meptyl and MCPA. The future climate projections used here resulted in only minor changes in predicted exposure concentrations and thereby future risk. However, a stronger increase in risk was predicted for the scenarios with increased pesticide application, which can represent an adaptation to a future climate with higher pest pressures. In the current study, the specific BN model predictions were constrained by an existing set of climate projections which represented only one IPCC scenario (A1B) and two climate models. Further advancement of the BN modelling demonstrated herein, including more recent climate scenarios and a larger set of climate models, is anticipated to result in more relevant risk characterization also for future climate conditions. This probabilistic approach will have the potential to aid targeted management of ecological risks in support of future research, industry and regulatory needs.
Forfattere
Britt Puidet Romain Mabon Michele Guibert Riinu Kiiker Liina Soonvald Vinh Hong Le Håvard Eikemo Pauline Dewaegeneire Guillaume Saubeau Catherine Chatot Frederique Aurousseau David E. L. Cooke Alison K. Lees Isaac K. Abuley Jens G. Hansen Roselyne Corbiere Melen Leclerc Didier AndrivonSammendrag
Until recently, genotypes of Phytophthora infestans were regionally distributed in Europe, with populations in western Europe being dominated by clonal lineages and those in northern Europe being genetically diverse because of frequent sexual reproduction. However, since 2013 a new clonal lineage (EU_41_A2) has successfully established itself and expanded in the sexually recombining P. infestans populations of northern Europe. The objective of this study was to study phenotypic traits of the new clonal lineage of P. infestans, which may explain its successful establishment and expansion within sexually recombining populations. Fungicide sensitivity, aggressiveness, and virulence profiles of isolates of EU_41_A2 were analyzed and compared with those of the local sexual populations from Denmark, Norway, and Estonia. None of the phenotypic data obtained from the isolates collected from Denmark, Estonia, and Norway independently explained the invasive success of EU_41_A2 within sexual Nordic populations. Therefore, we hypothesize that the expansion of this new genotype could result from a combination of fitness traits and more favorable environmental conditions that have emerged in response to climate change.
Forfattere
Katherine Ann Gredvig Nielsen Magne Nordang Skårn Venche Talgø Martin Petterson Inger Sundheim Fløistad Gunn Mari Strømeng May Bente Brurberg Arne StensvandSammendrag
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