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.
2020
Sammendrag
Ornamental jewelweed (Impatiens glandulifera Royle) is an alien invasive plant in Europe. This annual plant often grows in riparian habitats where herbicides are prohibited. Several studies have reported the negative effect on ecosystem and ecosystem services by this species. However, limited research is published on control measures and the aim of our study was to explore use of hot water and cutting to control I. glandulifera. A lab experiment showed that the lethal water temperature for seed was between 45 and 50 C. In a pot experiment with seeds in soil, emergence of I. glandulifera was reduced by 78% and 93% compared with the untreated control with volumes of hot water (80 C) of 7.2 and 14.5 L m−2, respectively. When treatments were conducted on relatively tall plants (almost 60 cm) in late June, hot water gave significantly better control than cutting. Compared with an untreated control, I. glandulifera cover was reduced by 97% and 79% after hot water and cutting, respectively. Application of hot water to smaller (<40 cm) and less developed plants (BBCH 12–13) in early June and cutting of plants with visible flower buds (mid-July) led to no significant difference in cover. Compared with an untreated control, I. glandulifera cover was reduced by 99% (cut below first node) and 91% (hot water and cut above first node). When relatively tall plants (almost 60 cm) were treated, hot water use was high (31.1 L m−2) and required twice as many work hours (4.8 min m−2) as cutting (2.4 min m−2). When smaller plants (<40 cm) were targeted, work hours and hot water use were reduced to 2.1 min m−2 and 13.7 L m−2, respectively.
Sammendrag
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Sammendrag
BACKGROUND Pollen beetles are key pests in oilseed rape (OSR) production. These beetles use visual and olfactory cues to locate their host plants at specific phenological stages, hence trap cropping may represent an alternative pest control strategy. In this study, a trap crop strategy for spring OSR was developed. To elaborate such a trap cropping system, a pest control measure that eradicates the attracted beetles in the trap crop before they migrate further into the main crop was included in the final trap cropping strategy. RESULTS Testing yellow‐flowering turnip rape and one yellow‐ and two cream‐coloured flowering OSR cultivars as potential crops in different trap cropping strategies, we found that pollen beetles clearly preferred turnip rape over the cream‐coloured and yellow OSR cultivars, and preferred the yellow OSR cultivar over the two cream‐coloured cultivars. This behaviour was related to the plant growth stage and associated volatile and colour signals of the tested cultivars. Using turnip rape as a trap crop and testing kairomone‐ or insecticide‐assisted trap cropping as the pest control strategy was as effective as compared with whole fields treated with a standard pesticide. CONCLUSION Combining a turnip rape cultivar as trap crop with kairomone traps placed in the trap crop as a killing agent may enable renunciation of pesticides in spring OSR production. © 2020 Society of Chemical Industry
Forfattere
Bjørn Egil FløSammendrag
Det er ikke registrert sammendrag
Forfattere
Greeley BeckSammendrag
Research Highlights: Polyesterification of wood with sorbitol and citric acid (SCA) increases decay resistance against brown-rot and white-rot fungi without reducing cell wall moisture content but the SCA polymer is susceptible to hydrolysis. Background and Objectives: SCA polyesterification is a low-cost, bio-based chemical wood modification system with potential for commercialisation. Materials and Methods: This study investigates moisture-related properties and decay resistance in SCA-modified wood. Scots pine sapwood was polyesterified at 140 ◦C with various SCA solution concentrations ranging from 14–56% w/w. Dimensional stability was assessed and leachates were analysed with high-performance liquid chromatography (HPLC). Chemical changes were characterized with attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and spectra were quantitatively compared with peak ratios. Low-field nuclear magnetic resonance (LFNMR) relaxometry was used to assess water saturated samples and decay resistance was determined with a modified EN113 test. Results: Anti-swelling efficiency (ASE) ranged from 23–43% and decreased at higher weight percentage gains (WPG). Reduced ASE at higher WPG resulted from increased water saturated volumes for higher treatment levels. HPLC analysis of leachates showed detectable citric acid levels even after an EN84 leaching procedure. ATR-FTIR analysis indicated increased ester content in the SCA-modified samples and decreased hydroxyl content compared to controls. Cell wall water assessed by non-freezing moisture content determined with LFNMR was found to increase because of the modification. SCA-modified samples resisted brown-rot and white-rot decay, with a potential decay threshold of 50% WPG. Sterile reference samples incubated without fungi revealed substantial mass loss due to leaching of the samples in a high humidity environment. The susceptibility of the SCA polymer to hydrolysis was confirmed by analysing the sorption behaviour of the pure polymer in a dynamic vapour sorption apparatus. Conclusions: SCA wood modification is an effective means for imparting decay resistance but, using the curing parameters in the current study, prolonged low-level leaching due to hydrolysis of the SCA polymer remains a problem.
Forfattere
Taru Sandén Heide Spiegel Hannah Tabea Wenng Michael Schwarz Judith M. SarneelSammendrag
The decay of organic material—litter decomposition—is a critical process for life on Earth and an essential part of the global carbon cycle. Yet, this basic process remains unknown to many citizens. The Tea Bag Index (TBI) measures decomposition in a standardized, measurable, achievable, climate-relevant, and time-relevant way by burying commercial tea bags in soil for three months and calculating proxies to characterize the decomposition process (expressed as decomposition rate (k) and stabilization factor (S)). We measured TBI at 8 cm soil depth with the help of school and farm citizen scientists in 2015 in Sweden and in 2016 in Austria. Questionnaires to the participating schools and farms enabled us to capture lessons learned from this participatory data collection. In total >5500 citizen scientists participated in the mass experiments, and approximately 50% of the tea bags sent out yielded successful results that fell well within previously reported ranges. The average decomposition rates (k) ranged from 0.008 to 0.012 g d−1 in Sweden and from 0.012 to 0.015 g d−1 in Austria. Stabilization factors (S) were up to four times higher in Sweden than Austria. Taking part in a global experiment was a great incentive for participants, and in future experiments the citizen scientists and TBI would benefit from having enhanced communication between the researchers and participants about the results gained.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Selamawit Araya Kidane Beira H. Meressa Solveig Haukeland Trine Hvoslef-Eide Christer Magnusson Marjolein Couvreur Wim Bert Danny L. CoyneSammendrag
Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.
Sammendrag
Root-associated entomopathogenic fungi (R-AEF) indirectly infuence herbivorous insect performance. However, host plant-R-AEF interactions and R-AEF as biological control agents have been studied independently and without much attention to the potential synergy between these functional traits. In this study, we evaluated behavioral responses of cabbage root fies [Delia radicum L. (Diptera: Anthomyiidae)] to a host plant (white cabbage cabbage Brassica oleracea var. capitata f. alba cv. Castello L.) with and without the R-AEF Metarhizium brunneum (Petch). We performed experiments on leaf refectance, phytohormonal composition and host plant location behavior (behavioral processes that contribute to locating and selecting an adequate host plant in the environment). Compared to control host plants, R-AEF inoculation caused, on one hand, a decrease in refectance of host plant leaves in the near-infrared portion of the radiometric spectrum and, on the other, an increase in the production of jasmonic, (+)-7-iso-jasmonoyl-l-isoleucine and salicylic acid in certain parts of the host plant. Under both greenhouse and feld settings, landing and oviposition by cabbage root fy females were positively afected by R-AEF inoculation of host plants. The fungal-induced change in leaf refectance may have altered visual cues used by the cabbage root fies in their host plant selection. This is the frst study providing evidence for the hypothesis that R-AEF manipulate the suitability of their host plant to attract herbivorous insects.
Sammendrag
Phosphorus is an essential plant nutrient, but primary resources are limited and overfertilization may cause eutrophication of freshwater. Our objectives were to examine temperature effects on (a) optimal P rate for turfgrass establishment, and (b) increasing rates of foliar vs. granular P for early spring growth of established greens. Two trials, both on USGA root zones and replicated in April−May over 2 yr, were conducted in daylight phytotrons at 7, 12 and 17 °C. Experiment 1 compared 5 P rates from 0 to 0.48 g P m−2 wk−1 for creeping bentgrass establishment on a sand containing 13 mg P kg−1 (Mehlich‐3). Results showed no temperature effect on the optimal P rate. Bentgrass coverage and clipping yield increased up to 0.12 and 0.24 g P m−2 wk−1, corresponding to 6 and 12% of the N input, respectively. The concentration of P in clippings was higher at 7 than at 17 °C indicating that temperature was more limiting to shoot growth than to P uptake. A higher root/top ratio showed that plants invested more in roots under P deficiency. Experiment 2 was conducted using intact cores from a 4‐yr‐old creeping bentgrass (Agrostis stolonifera L.) green with a Mehlich‐3 P level of 34 mg P kg−1. Results showed increased clipping yields up to 0.18 g P m−2 wk−1 and higher P uptake with granular than with foliar application, but there was no effect on turfgrass color and no interaction with temperature. Low temperatures did not justify higher P applications.