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.
2017
Authors
Anja Karine Ruud Susanne Skinnehaugen Windju Andrea Ficke Jon Arne Dieseth Timothy L. Friesen Morten LillemoAbstract
No abstract has been registered
Authors
Andrea FickeAbstract
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Abstract
Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring-sown white clover sward (three experiments) or during autumn, post-cereal harvest, in an under-sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.
Abstract
During the past two decades, significant spread of the perennial weeds Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in coastal parts of Norway seems to have coincided with an observed rise in winter temperatures. This study investigated the frost tolerance (LT50) and effects of moderate frost exposure on rush plant regrowth over time during the period late November to late winter/spring, and photosynthetic activity in late winter/spring. Juncus effusus and J. conglomeratus of physiologically young age (seedlings) displayed similar high frost tolerance (LT50) and did not differ significantly in regenerative ability following prolonged frost exposure. Regrowth capacity generally increased during winter and when stress conditions increased, shoot formation was prioritised over total biomass production. Maximum quantum efficiency of photosystem II (Fv/Fm) and performance index of photosystem II (PI) were high in late winter/spring, with J. effusus showing higher values than J. conglomeratus. Green, photosynthetically active shoots, which facilitate accumulation of carbohydrates during autumn and even in winter, may provide Juncus spp. with substantial competitiveness in late winter and spring. The results revealed that the dominance of J. effusus over J. conglomeratus in pastures and leys is not due to major differences in winter survival parameters, but probably the higher photosynthetic efficiency observed in J. effusus. Generally higher temperatures during winter and lower frost kill may be contributing to the current increase in rush infestation.
Abstract
No abstract has been registered
Authors
Phyllis G. Weintraub Sonja J. Scheffer Diedrich Visser Graciela Valladares Alberto Soares Correa B. Merle Shepard Aunu Rauf Sean T. Murphy Norma Mujica Charles MacVean Jürgen Kroschel Miriam Kishinevsky Ravindra C. Joshi Nina Johansen Rebecca H. Hallett Hasan S. Civelek Bing Chen Helga Blanco MetzlerAbstract
Liriomyza huidobrensis (Blanchard) is native to South America but has expanded its range and invaded many regions of the world, primarily on flowers and to a lesser extent on horticultural product shipments. As a result of initial invasion into an area, damage caused is usually significant but not necessarily sustained. Currently, it is an economic pest in selected native and invaded regions of the world. Adults cause damage by puncturing abaxial and adaxial leaf surfaces for feeding and egg laying sites. Larvae mine the leaf parenchyma tissues which can lead to leaves drying and wilting. We have recorded 365 host plant species from 49 families and more than 106 parasitoid species. In a subset of the Argentinian data, we found that parasitoid community composition attacking L. huidobrensis differs significantly in cultivated and uncultivated plants. No such effect was found at the world level, probably due to differences in collection methods in the different references. We review the existing knowledge as a means of setting the context for new and unpublished data. The main objective is to provide an update of widely dispersed and until now unpublished data, evaluate dispersion of the leafminer and management strategies in different regions of the world, and highlight the need to consider the possible effects of climate change on further regional invasions or expansions.
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Abstract
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Abstract
No abstract has been registered