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.
2007
Authors
P Benoit J Perceval Marianne Stenrød C Moni Ole Martin Eklo E Barriuso Tore E. Sveistrup Jens KværnerAbstract
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Authors
Karlsson Magnus Ari Hietala Harald Kvaalen Halvor Solheim Åke Olson Jan Stenlid Carl Gunnar FossdalAbstract
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Abstract
In spring 2002, extensive damage was recorded in southeast Norway on nursery-grown Norway spruce seedlings that had either wintered in nursery cold storage or had been planted out in autumn 2001. The damage was characterised by a top shoot dieback. Two visually distinct types of necroses were located either on the upper or lower part of the 2001-year-shoot. Isolations from the upper stem necroses rendered Gremmeniella abietina, while Phomopsis sp. was isolated mostly from the from the lower stem necroses. RAMS (random amplified microsatellites) profiling indicated that the G. abietina strains associated with diseased nursery seedlings belonged to LTT (large-tree type) ecotype, and inoculation tests confirmed their pathogenicity on Norway spruce seedlings. Phomopsis sp. was not pathogenic in inoculation tests, this implying it may be a secondary colonizer. We describe here the Gremmeniella - associated shoot dieback symptoms on Norway spruce seedlings and conclude that the unusual disease outburst was related to the Gremmeniella epidemic caused by the LTT type on large pines in 2001. The role of Phomopsis sp. in the tissue of diseased Norway spruce seedlings is yet unclear.
Abstract
Host tree terpenes can influence attraction of conifer-infesting bark beetles to their aggregation pheromones, and both synergistic and inhibitory effects have been reported. We tested a gradient of ratios of (–)-α-pinene, the predominant monoterpene in Norway spruce, to the pheromone of Ips typographus, a major pest of Norway spruce. Attraction of I. typographus increased as the release rate of (–)-α-pinene increased. The two highest (–)-α-pinene : pheromone ratios (526 : 1 and 2595 : 1) attracted twice as many I. typographus as pheromone alone, whereas low to intermediate ratios (56 : 1, 274 : 1) did not differ from pheromone alone. Our results are in agreement with a proposed model, which suggests that bark beetles display unique response profiles to host terpenes depending on the physiological condition of the host trees that they typically colonize. Ips typographus, which is an aggressive species capable of colonizing and killing healthy trees, showed an increased attraction to monoterpene : pheromone ratios, and this may be high enough to inhibit attraction of less aggressive beetle species typically colonizing dead, dying or stressed trees. Attraction of associates of I. typographus was also modified by (–)-α-pinene. Ips duplicatus, a competitor of I. typographus, showed increased attraction to the pheromone of I. typographus across all concentrations of (–)-α-pinene.
Authors
Sanna Koutaniemi Tino Warinowski Anna Karkonen Edward Alatalo Carl Gunnar Fossdal Pekka Saranpaa Tapio Laakso Kurt V. Fagerstedt Liisa K. Simola Lars Paulin Stephen Rudd Teemu H. TeeriAbstract
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2006
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Abstract
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