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.
2011
Forfattere
Venche TalgøSammendrag
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Forfattere
Oskar PuschmannSammendrag
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Forfattere
Atle Mysterud Leif Egil Loe Erling Meisingset Barbara Zimmermann Arne William Hjeltnes Vebjørn Veiberg Inger Maren Rivrud Anders Skonhoft Jon Olaf Olaussen Oddgeir Andersen Richard Bischof Christophe Bonenfant Øystein Brekkum Rolf Langvatn Hallvard Flatjord Ivar Syrstad Arve Aarhus Vidar HoltheSammendrag
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Sammendrag
Colletotrichum acutatum causes black spot in strawberry (Fragaria × ananassa), but it has also been isolated from 30 other cultivated and non-cultivated plant species in Norway, including almost all fruit and berry crops. Bitter rot, which is caused by C. acutatum, is a severe disease in sweet and sour cherry and apple. We have studied the possibility of cross infection of isolates from other hosts and the potential aggressiveness of these isolates on strawberry. Molecular analyses (AFLP) have shown that isolates collected in Norway could be separated into three major phylogenetic groups in which isolates collected from either Prunus spp., Malus domestica or Fragaria × ananassa predominated. Experiments were carried out under laboratory, greenhouse and field conditions, and strawberry fruits, leaves and stolons were inoculated. All experiments showed that isolates originating from the Fragaria group was much more aggressive than those from the other two groups. If detached strawberry fruits were wounded at time of inoculation, isolates from all groups developed black spot, but disease development went much slower for isolates from the Prunus or Malus groups. If not wounded, there was no or hardly any disease development caused by isolates from the latter two groups. On whole plants inoculated in the greenhouse, isolates in the Fragaria group developed an incidence of 27 to 28 % flower and fruit infections compared to 0 to 4 % for isolates from the other two groups. Under field conditions, Fragaria group isolates developed 50 to 70 % more infected fruit than the others at harvest. On stolons, we inoculated by wounding, and differences in aggressiveness between isolates were only minor. On strawberry leaf laminas, we observed that the ability to colonize the leaf surface was much larger for isolates from the Fragaria group compared to those from the other two groups. However, planting healthy strawberry transplants adjacent to infected sweet cherry trees resulted in latent infections of C. acutatum on strawberry leaves (but no visible infections on fruits), indicating that cross infection between host species may occur under field conditions.
Sammendrag
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Forfattere
Hans Ragnar Norli Geir Kjølberg Knudsen Marco TasinSammendrag
Kairomones intersecting host searching females is an attractive method for species-specific pest control. Apple fruit moth, Argyresthia conjugella, is a major pest of apples in Fennoscandia. The severity of the attacks on apple happens as a response to large scale masting in the moths principal host rowan, Sorbus aucuparia. Co-occurrence of volatile compounds in rowan and apple is suggested to facilitate the forced host shift. The apple fruit moth responds to odour from its principal host with upwind orientation in a wind tunnel. Host responding apple fruit moths have high plasticity to blend ratios suggesting why a specialist insect can locate alternative host during intermast years and damage apples. However, even with all host compounds present, distortions of blend ratios seriously jeopardize upwind orientation in laboratory bioassays. In a combined approach with wind tunnel bioassays and field trapping, we have now identified a seven-component blend which is highly attractive for gravid female apple fruit moths. The new blend is especially attractive in apple crops, showing high odour competition compared to the secondary host. Verification of the blend in monitoring to achieve increased precision of pesticide sprays, establishment of economic damage thresholds and mass trapping is ongoing.
Sammendrag
We treated Norway spruce (Picea abies) stems with methyl jasmonate (MeJA) to determine possible quantitative and qualitative eVects of induced tree defenses on pheromone emission by the spruce bark beetle Ips typographus. We measured the amounts of 2-methyl-3-buten-2-ol and (S)-cis-verbenol, the two main components of the beetle’s aggregation pheromone, released from beetle entrance holes, along with phloem terpene content and beetle performance in MeJA-treated and untreated Norway spruce logs. As expected, phloem terpene levels were higher and beetle tunnel length was shorter (an indication of poor performance) in MeJA-treated logs relative to untreated logs. Parallel to the higher phloem terpene content and poorer beetle performance, beetles in MeJA-treated logs released signiWcantly less 2-methyl-3-buten-2-ol and (S)-cis-verbenol, and the ratio between the two pheromone components was signiWcantly altered. These results suggest that host resistance elicited by MeJA application reduces pheromone emission by I. typographus and alters the critical ratio between the two main pheromone components needed to elicit aggregation. The results also provide a mechanistic explanation for the reduced performance and attractivity observed in earlier studies when bark beetles colonize trees with elicited host defenses, and extend our understanding of the ecological functions of conifer resistance against bark beetles.
Forfattere
grete h m jørgensen K. M. BøeSammendrag
Housing of horses in Norway - an overview Grete H.M. Jørgensen1 and Knut E. Bøe2 1Bioforsk, National Institute for Agricultural and Environmental Research, Tjøtta Norway2Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, UMB, ås Norway Corresponding author: +47 40 76 67 69 e-mail grete.jorgensen@bioforsk.no Similar to the National regulations for cattle, poultry and pigs the Norwegian regulation for the welfare of horses also states that horse owners should facilitate social contact for their horses. Nevertheless, it is quite common that horses are kept individually or even isolated from others throughout the year. Chronic obstructive pulmonary diseases are an increasing problem in the horse population and bad air quality in stables may contribute largely to this disease. Stables with fewer than ten horses do not have to register with the National Food Safety Authorities, and a public register of stables is not available. The aim of this study was therefore to provide an overview of the current management and living conditions for trotting horses in Norway. We wanted to focus both on the outdoor and indoor environment and investigate which ventilation systems that are commonly used in stable buildings. With help from the National Trotting Association (DNT) we sent out a questionnaire to members of their local branches in order to ensure answers from all areas of Norway. In each local branch we selected four to five stables after the following criteria: one small stable with 1-2 horses, to or three medium sized stables with 3-10 horses and the largest stable in that area. The questionnaire consisted of 32 questions divided into four subcategories: management, stable environment, ventilation and outdoor areas and paddocks. 275 (61%) of the 442 initial questionnaires were returned. Seven of these were however disregarded due to incomplete answers. The results were therefore finally based on 268 stables, 38 small stables (1-2 horses), 164 medium sized stables (3-10 horses) and 60 large stables (>10 horses). The data included over 2400 horses. More than half of the stable buildings had earlier been used for other purposes (56.4%). The majority of the stable buildings were insulated (83.6%), while a few had non-insulated stables (10.1%) or shelters with three walls and a roof (1.1%). Most stables had mechanical ventilation with a fan (49.6%), while 38.4% indicated that their stable had natural ventilation. Among the stable owners that indicated having natural ventilation in the stable, only 23.1% (8.9% of all stables) had non-insulated buildings and ventilation through adjustable openings, while 76.9% (29.8%) had insulated buildings and ensured airflow through opening doors and windows. A total lack of ventilation was indicated by 4.9% of the stable owners while 0.4% did not know what type of ventilation the stable had. In addition to this, 2.6% of the stable owners had most of their horses in 24 hour loose housing outdoors with open shelters and a ventilation system was therefore not necessary. Individual housing in boxes indoors dominated (84% of all stables), while very few horses were kept in outdoor boxes (1.1%). Other housing methods were tie-stalls 1.5%), 24 hour loose housing outdoors (3.4%), both tie-stalls and individual boxes (6.0%) and tie-stalls or boxes combined with group housing or several horses in the same box (1.1%). Six of the 38 small stables had only one horse which consequently was kept alone, while 34% of the small stables kept their horses in separate paddocks. Only 15% of the medium sized stables kept the horses in individual paddocks and 80.4% kept two or more horses together during turn-out. Ninety percent of the large stables indicated that they allowed two or more horses to share paddocks during turn-out. In conclusion, Norwegian trotting horses are mainly housed in individual boxes indoors and many stables have a ventilation system that does not work properly. Most trotting horses have access to a paddock or pasture on a daily basis. Housing and management of horses in other disciplines should also be investigated.
Forfattere
Grete Helen Meisfjord Jørgensen Knut Egil BøeSammendrag
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Forfattere
Knut Egil Bøe Grete Helen Meisfjord JørgensenSammendrag
Det er ikke registrert sammendrag