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.
2025
Authors
Volkmar Timmermann Nenad Potočić Anne-Katrin Prescher Alexa Michel Katrin Haggenmüller Till KirchnerAbstract
In 2024, our sample remained stable with 27 participating countries and the largest number of assessed plots since 2019. We witnessed a very slight increase of 0.2 percentage points (%p) in mean defoliation as compared to 2023, mainly due to an increase of 0.5%p for broadleaves, while defoliation of conifers remained almost unchanged (0.1%p decrease). The strongest increase in defoliation occurred in deciduous (sub-) Mediterranean oaks (+2.1%p), while the strongest decrease was recorded in Norway spruce (-0.8%p). Deciduous temperate oaks had the highest (29.7%) and Norway spruce the lowest (22.4%) mean defoliation. Trend analyses show a considerable increase in defoliation of evergreen oaks (7.1%p), common beech (6%p), Norway spruce (5.5%p), and deciduous temperate oaks (5%p) over the past 20 years. The increase in defoliation for Scots pine and Mediterranean lowland pines (3.7 and 3.3%p, respectively) was more moderate. The results of the trend analyses were not significant for deciduous (sub-) Mediterranean oaks and Austrian pine. The percentage of trees with damage symptoms (48.6%) was almost the same as in 2023 (-0.5%p). As in previous years, the number of damage symptoms per assessed tree was substantially higher for broadleaves than for conifers (0.86 vs. 0.55, respectively). Insects, abiotic causes, and fungi were the most common damage agent groups for all species, comprising altogether more than half of all damage records. Tree mortality in 2024 was 1.1% (1 145 trees), i.e. at the same level as in the year before. While mortality rates for the main species and species groups ranged from 0.6 to 1.6%, mortality of Betula spp. and European ash was higher with 2.4% and 7% respectively.
Authors
Volkmar TimmermannAbstract
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Authors
Lena Wohlgemuth Mathieu Jonard Andreas Schmitz Peter Waldner P. Schmidt Walter Heleen Deroo Nathalie Cools Bruno de Vos Anne Thimonier Arne Verstraeten Inken Krüger Volkmar Timmermann Mathias Neumann Pasi Rautio Kai SchwärzelAbstract
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Authors
Heidi Udnes AamotAbstract
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Abstract
Leather rot of strawberry fruit caused by the oomycete Phytophthora cactorum is detrimental to both freshly consumed and processed produce of this crop because of an off-odour flavour caused by two phenolic compounds, 4-ethylphenol (4-EP) and 4-ethyl-2-methoxyphenol (4-ethyl guaiacol, 4-EG). In this study, we have investigated differences in off-odour among strawberry genotypes and how the perception of the off-odour varies among people. Fruit of 13 strawberry genotypes, including five cultivars and eight selections, inoculated with P. cactorum were assessed by a sensory panel to determine differences in the characteristic leather rot odour. The content of aroma compounds, including the two phenolics, was analysed by headspace GC/MS and compared with sensory analysis. The amount of 4-EP and 4-EG varied greatly among the genotypes, and although the ones with the highest and lowest sensory scores also had the highest and lowest amounts of the phenolics, the correlation between their content and leather rot odour was not significant. The results clearly indicated that aroma components, of which the major ones were butanoic acid and acetic acid methyl and ethyl esters, hexanoic acid methyl ester and acetone, were important for the perception of leather rot off-odour. This suggests that natural strawberry aroma compounds can partly mask the characteristic leather rot odour independent of the level of the off-odour compounds. Consumer tests showed great variation in the ability of people to recognize the leather rot off-odour of strawberry fruit, especially at lower levels, but a few people were not able to detect the odour at all. The amount of contaminated strawberry fruit necessary for olfactory identification and to set an odour threshold of leather rot is further discussed.