Blar i Vitenskapelige artikler på forfatter "Hjelkrem, Anne-Grete Roer"
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Are fungal epizootics a sign of successful biological control of cereal aphids?
Saussure, Stephanie; Hjelkrem, Anne-Grete Roer; Klingen, Ingeborg; Meadow, Richard; Holst, Niels (Peer reviewed; Journal article, 2023-07-26)Pandora neoaphidis is a common entomopathogenic fungus on Sitobion avenae, which is an important aphid pest on cereals in Europe. Pandora neoaphidis is known to cause epizootics (i.e. an unusually high prevalence of infected ... -
Distribution of the Infection Time of Ascospores of Venturia inaequalis
Philion, Vincent; Joubert, Valentin; Trapman, Marc; Hjelkrem, Anne-Grete Roer; Stensvand, Arne (Journal article; Peer reviewed, 2019-02)In many areas where spring is wet, fungicides are applied in relation to rain events that trigger ejection of ascospores of Venturia inaequalis, which cause primary infections of apple scab. Past studies established the ... -
The effect of climate variability in the efficacy of the entomopathogenic fungus Metarhizium acridum against the desert locust Schistocerca gregaria
Kamga, Samuel F.; Ndjomatchoua, Frank T.; Guimapi, Ritter A.; Klingen, Ingeborg; Tchawoua, Clément; Hjelkrem, Anne-Grete Roer; Thunes, Karl H; Kakmeni, Francois M. (Peer reviewed; Journal article, 2022-05-09)Despite substantial efforts to control locusts they remain periodically a major burden in Africa, causing severe yield loss and hence loss of food and income. Distribution maps indicating the value of the basic reproduction ... -
Effect of three isolates of Pandora neoaphidis from a single population of Sitobion avenae on mortality, speed of kill and fecundity of S. avenae and Rhopalosiphum padi at different temperatures
Saussure, Stephanie; Westrum, Karin; Hjelkrem, Anne-Grete Roer; Klingen, Ingeborg (Journal article; Peer reviewed, 2019)We studied the effect of three Pandora neoaphidis isolates from one Sitobion avenae population, three temperatures, and two aphid species namely S. avenae and Rhopalosiphum padi on (i) aphid mortality, (ii) time needed to ... -
Environmental Impact of Feeding with Infant Formula in Comparison with Breastfeeding
Andresen, Ellen Cecilie; Hjelkrem, Anne-Grete Roer; Bakken, Anne Kjersti; Andersen, Lene Frost (Peer reviewed; Journal article, 2022-05-24)Young children have unique nutritional requirements, and breastfeeding is the best option to support healthy growth and development. Concerns have been raised around the increasing use of milk-based infant formulas in ... -
Environmental impacts along intensity gradients in Norwegian dairy production as evaluated by life cycle assessments
Bakken, Anne Kjersti; Daugstad, Kristin; Johansen, Astrid; Hjelkrem, Anne-Grete Roer; Fystro, Gustav; Strømman, Anders Hammer; Korsæth, Audun (Journal article; Peer reviewed, 2017-09-18)The aim of the study was to explore whether and how intensification would contribute to more environmentally friendly dairy production in Norway. Three typical farms were envisaged, representing intensive production ... -
HT-2 and T-2 toxins in Norwegian oat grains related to weather conditions at different growth stages
Hjelkrem, Anne-Grete Roer; Aamot, Heidi Udnes; Brodal, Guro; Strand, Einar; Torp, Torfinn; Edwards, Simon G.; Dill-Macky, Ruth; Hofgaard, Ingerd Skow (Journal article; Peer reviewed, 2018-01-08)High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing ... -
Life cycle assessment of tomato production for different production strategies in Norway
Naseer, Muhammad; Persson, Tomas; Hjelkrem, Anne-Grete Roer; Ruoff, Peter; Verheul, Michel (Peer reviewed; Journal article, 2022-08-30)The availability of fresh vegetables grown in greenhouses under controlled conditions throughout the year has given rise to concerns about their impact on the environment. In high latitude countries such as Norway, greenhouse ... -
NORNE, a process-based grass growth model accounting for within-field soil variation using remote sensing for in-season corrections
Hjelkrem, Anne-Grete Roer; Geipel, Jakob; Bakken, Anne Kjersti; Korsæth, Audun (Peer reviewed; Journal article, 2023-06-06)A process-based model was developed to predict dry matter yields and amounts of harvested nitrogen in conventionally cropped grassland fields, accounting for within-field variation by a node network design and utilizing ... -
Prediction of leaf Bloch disease risk in Norwegian spring wheat based on weather factors and host phenology
Hjelkrem, Anne-Grete Roer; Ficke, Andrea; Abrahamsen, Unni; Hofgaard, Ingerd Skow; Brodal, Guro (Peer reviewed; Journal article, 2021-02-17)Leaf blotch diseases (LBD), such as Septoria nodorum bloch (Parastagnospora nodorum), Septoria tritici blotch (Zymoseptoria tritici) and Tan spot (Pyrenophora tritici-repentis) can cause severe yield losses (up to 50%) in ... -
A process-based model to forecast risk of potato late blight in Norway (The Nærstad model): model development, sensitivity analysis and Bayesian calibration
Hjelkrem, Anne-Grete Roer; Le, Vinh Hong; Hermansen, Arne; Nærstad, Ragnhild (Peer reviewed; Journal article, 2021-04-23)Late blight caused by Phytophthora infestans is a serious, worldwide disease on potato (Solanum tuberosum). Phytophthora infestans normally reproduces in a clonal manner, but in some areas, as the Nordic Countries, sexual ... -
Sensitivity analysis and Bayesian calibration for testing robustness of the BASGRA model in different environments
Hjelkrem, Anne-Grete Roer; Höglind, Mats; Van Oijen, Marcel; Schellberg, Jürgen; Gaiser, Thomas; Ewert, Frank (Journal article; Peer reviewed, 2017-09-10)Proper parameterisation and quantification of model uncertainty are two essential tasks in improvement and assessment of model performance. Bayesian calibration is a method that combines both tasks by quantifying probability ... -
Weather Patterns Associated with DON Levels in Norwegian Spring Oat Grain: A Functional Data Approach
Hjelkrem, Anne-Grete Roer; Aamot, Heidi Udnes; Lillemo, Morten; Sørensen, Espen Sannes; Brodal, Guro; Russenes, Aina Lundon; Edwards, Simon G.; Hofgaard, Ingerd Skow (Peer reviewed; Journal article, 2021-12-27)Fusarium graminearum is regarded as the main deoxynivalenol (DON) producer in Norwegian oats, and high levels of DON are occasionally recorded in oat grains. Weather conditions in the period around flowering are reported ...