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.
2020
Abstract
Cereal grain contaminated by Fusarium mycotoxins is undesirable in food and feed because of the harmful health effects of the mycotoxins in humans and animals. Reduction of mycotoxin content in grain by cleaning and size sorting has mainly been studied in wheat. We investigated whether the removal of small kernels by size sorting could be a method to reduce the content of mycotoxins in oat grain. Samples from 24 Norwegian mycotoxin-contaminated grain lots (14 from 2015 and 10 from 2018) were sorted by a laboratory sieve (sieve size 2.2 mm) into large and small kernel fractions and, in addition to unsorted grain samples, analyzed with LC-MS-MS for quantification of 10 mycotoxins. By removing the small kernel fraction (on average 15% and 21% of the weight of the samples from the two years, respectively), the mean concentrations of HT-2+T-2 toxins were reduced by 56% (from 745 to 328 µg/kg) in the 2015 samples and by 32% (from 178 to 121 µg/kg) in the 2018 samples. Deoxynivalenol (DON) was reduced by 24% (from 191 to 145 µg/kg) in the 2018 samples, and enniatin B (EnnB) by 44% (from 1059 to 594 µg/kg) in the 2015 samples. Despite low levels, our analyses showed a trend towards reduced content of DON, ADON, NIV, EnnA, EnnA1, EnnB1 and BEA after removing the small kernel fraction in samples from 2015. For several of the mycotoxins, the concentrations were considerably higher in the small kernel fraction compared to unsorted grain. Our results demonstrate that the level of mycotoxins in unprocessed oat grain can be reduced by removing small kernels. We assume that our study is the first report on the effect of size sorting on the content of enniatins (Enns), NIV and BEA in oat grains.
Abstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Till Seehusen Hugh Riley Ruth Dill-Macky Børge Holen Guro BrodalAbstract
To mitigate the risk of erosion and nutrient runoff, reduced tillage has become more prevalent in Norway. Within within recent decades, there have been some years with relatively high occurrence of Fusarium head blight and mycotoxins in Norwegian cereal grain. This is thought to have been caused by an increased inoculum potential (IP) of Fusarium spp. due to larger amount of crop residues remaining on the soil surface, in combination with weather conditions promoting fungal growth and infection of cereal plants. The objective of this work was to elucidate the influence of different tillage practices on the IP of Fusarium spp. and the subsequent Fusarium-infection and mycotoxin contamination of spring wheat grain at harvest. Tillage trials were conducted at two locations in southeast Norway (Solør and Toten) over three years, 2010-2012. Residues of wheat from the previous year were collected in spring. Fusarium avenaceum and Fusarium graminearum were the most common Fusarium species recorded on wheat straw residues. IP was calculated as the percentage of the residues infested with Fusarium spp. multiplied by the proportion of the soil surface covered with residues. The IP of Fusarium spp. was lower in ploughed plots compared to those tilled with harrowing only. Ploughing in spring resulted in a similarly low IP as autumn ploughing. In contrast, harrowing in autumn generally reduced IP more than did spring harrowing. The mycotoxin levels in the harvested wheat were generally low, except for deoxynivalenol at high levels in Solør 2011. Despite a lower IP of ploughed versus harrowed plots, this was not reflected in the content of Fusarium and mycotoxins in harvested grain. The Fusarium species that dominated in the residues examined in this study were the same as those detected in the harvested grain, supporting the finding that residues are an important source of inoculum.
Authors
Guro Brodal Heidi Røsok Bye Eleonora Høst Martin Pettersson Inger Sundheim Fløistad Øyvind Meland Edvardsen Venche TalgøAbstract
Seedling blight caused by Sirococcus conigenus was recently reported on Norway spruce (Picea abies) from Norwegian forest nurseries. The inoculum source was found to be infected seeds. In a Petri dish assay, the fungicide fludioxonil + difenoconazole was, among other fungicides, found to inhibit mycelial growth of S. conigenus. This fungicide is formulated as a seed treatment and registered for cereals in Norway, and was chosen for an experiment to control S. conigenus on Norway spruce seeds. Samples from two naturally infected seed lots were treated with half, normal and double dose of the recommended rate for cereals. Together with untreated control samples, treated seeds were tested in the laboratory for efficacy against S. conigenus on potato dextrose agar (PDA) in Petri dishes and for germination potential on filter paper. We also recorded seed emergence in soil of one of the seed lots in a growth chamber and in a forest nursery. On agar, the fungus was not detected after seed treatment with fludioxonil + difenoconazole at any of the three dosages, but it was present in the control. Germination on filter paper and emergence in soil was high in both treated and untreated control seeds with no signs of detrimental effects from any of the three fungicide doses.
Abstract
In integrated pest management (IPM), the goal is to keep the impact of damaging agents below a threshold level with reduced pesticide use. The present review is focusing on IPM of fungal diseases and Phytophthora root rot in Norwegian Christmas tree plantations. Healthy transplants are of vital importance to give the production a good establishment. Sanitation of diseased material and weeds is also very important in IPM. Management strategies will vary with the disease-causing agent in question, therefore, correct identification is necessary. The major pathogens are within the kingdom’s Fungi (e.g. Neonectria neomacrospora) and Chromista (e.g. Phytophthora spp.). They depend on relatively high humidity or free moisture to spread and infect. Any factors diminishing the duration of wet conditions will, therefore, reduce the disease pressure. Efficient weed management in Christmas tree fields will increase air circulation and thereby ensure a quicker drying after precipitation. Furthermore, certain weed species are host plants for rust fungi on Christmas trees, and thus, removal of the alternate host is a highly relevant control strategy. In Norway, fungicide use in Christmas trees is limited and only recommended during the short period from bud break to fully elongated shoots, generally the most vulnerable period concerning fungal attacks.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Shiori Koga Heidi Udnes Aamot Anne Kjersti Uhlen Till Seehusen Eva Veiseth-Kent Ingerd Skow Hofgaard Anette Moldestad Ulrike BöckerAbstract
This study aims to understand the environmental factors, focusing on rain and fungal infection, affecting the assembly of glutenin polymers during grain maturation. Spring wheat was grown in the field and grains were sampled from 50% grain moisture until maturity. Grain moisture content, protein content, size of glutenin polymers, the presence of proteases, and the amount of DNA from common wheat pathogenic fungi were analysed. Rain influenced the rate of grain desiccation that occurred parallel to the rate of glutenin polymer assembly. Rapid desiccation contributed to faster glutenin polymer assembly than gradual desiccation. Severe reduction in the glutenin polymer size coincided with increased grain moisture due to rain. Furthermore, increased fungal DNA followed by presence of gluten-degrading proteases was observed in the grain after humid conditions. The presence of gluten-degrading proteases was presumably involved in reducing the size of glutenin polymers in grain. Our study gave new insight into how environmental conditions could be associated with the assembly of glutenin polymers during grain maturation. The results suggest that rain and/or fungal proteases play an important role in reducing the molecular size of glutenin polymers.
Abstract
No abstract has been registered
Authors
Olalla Díaz-Yáñez Blas Mola-Yudego Volkmar Timmermann Mari Mette Tollefsrud Ari Hietala Jonas OlivaAbstract
Determining the impacts of invasive pathogens on tree mortality and growth is a difficult task, in particular in the case of species occurring naturally at low frequencies in mixed stands. In this study, we quantify such effects by comparing national forest inventory data collected before and after pathogen invasion. In Norway, Fraxinus excelsior is a minor species representing less than 1% of the trees in the forests and being attacked by the invasive pathogen Hymenoscyphus fraxineus since 2006. By studying deviations between inventories, we estimated a 74% higher-than-expected average ash mortality and a 13% slower-than-expected growth of the surviving ash trees, indicating a lack of compensation by the remaining ash. We could confidently assign mortality and growth losses to ash dieback as no mortality or growth shifts were observed for co-occurring tree species in the same plots. The mortality comparisons also show regional patterns with higher mortality in areas with the longest disease history in Norway. Considering that ash is currently mostly growing in mixed forests and that no signs of compensation were observed by the surviving ash trees, a significant habitat loss and niche replacement could be anticipated in the mid-term.