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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

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Abstract

Fire blight, caused by Erwinia amylovora, was detected for the first time in Norway in 1986. It was a limited outbreak on the south-western coast, only on ornamentals, and particularly on Cotoneaster spp. An action group handling the eradication and containment of the disease was quickly established. Comprehensive statutory powers and resources were given by the government to do surveys and eradicate diseased or symptomless but highly susceptible plant species from contaminated areas. These activities have likely restricted fire blight to the western and southern coastal areas. Eastern and northern parts of Norway are considered free from fire blight. The disease has not been observed in important fruit-growing areas. Uncontrolled movement of beehives from areas with fire blight to areas free from the disease has contributed to its introduction to new areas. From 1969 to 2016 import of most host plants of E. amylovora from countries with fire blight was prohibited. A yearly program for annual surveys in parts of the country with commercial fruit-growing and nurseries, using digital maps on internet connected tablets with GPS and software for in situ registrations, proved to be an efficient method for discovering new outbreaks at an early stage, and to start eradication and thus limit further spread.

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Abstract

The fungus Neonectria neomacrospora has recently caused an epidemic outbreak in conifer species within the genus Abies in Denmark and Norway. Christmas tree producers in Europe and North America rely, to a large extent, on Abies species. The damage caused by N. neomacrospora, including dead shoot tips, red flagging of branches and potentially dead trees, have therefore caused concern about reduced quality and loss of trees, and thereby of revenue. Field observations of natural infection of 39 taxa, from 32 species, within the genus Abies in the Hørsholm Arboretum, Denmark, were evaluated; significant differences were seen between taxa, that is, species, and between some species and their subspecies. The Greek fir, Abies cephalonica, was the only species without damage. An inoculation experiment on detached twigs with mycelium plugs from a N. neomacrospora culture showed that all species could be infected. The damage observed in the inoculation experiment could explain 30% of the variation in the field observations based on species mean values. The epidemic outbreak and the high number of species susceptible to this fungus indicate that N. neomacrospora requires attention in the cultivation and conservation of Abies species.

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Abstract

Cultivars and cultivating methods for organic strawberry production were studied in experiments in open fields and high plastic tunnels during four cropping seasons in southern Norway. In open fields, flowers and fruits were attacked by grey mould when the flowering and harvest seasons were wet, and marketable yield was reduced by up to 20%. Production in high tunnels showed a potential of high yields of fruits of good quality when strawberry powdery mildew was controlled. Berry size varied significantly among the cultivars. ‘Frida’ had the largest fruits followed by ‘Sonata’ and ‘Florence’, while ‘Polka’, ‘Korona’ and ‘Iris’ had the smallest fruits. All cultivars yielded well, but due to fruit decay caused by grey mould the marketable yield was significantly reduced, especially in open field. Grey mould was the most important factor influencing marketable yields. Fruits from matted rows were largest, while the highest yield was obtained on woven polyethylene. There were no effects of mulching methods on marketable yield or the amount of fruits with grey mould. High tunnels with good control of pests and diseases showed a potential of high and stable yields of good quality.