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.
2008
Forfattere
Paal KrokeneSammendrag
Combined bark beetle-fungus attacks are a key factor in conifer ecosystems in the Northern Hemisphere, where they regularly cause massive tree mortality. Central to the success of the bark beetle-fungus complex is the fact that bark beetles are among the few insects that are capable of breaching the potent anatomical and chemical defenses of healthy tree stems.....
Sammendrag
Seed production in Norway spruce (Picea abies) seed orchards may be severely reduced by insects attacking cones and seeds. Insects in several orders and genera are responsible for the damage, and at present there are no effective and environmentally acceptable control options. Studies in Sweden have shown promising results with spraying Bt (Bacillus thuringiensis var. kurstaki x aizawai) against species of Lepidoptera, but for other pests other control methods must be developed....
Sammendrag
Tree-killing bark beetles conquer healthy trees by means of pheromone mediated mass-attacks. The initial attackers select trees through a process of random landing and processing of tactile and short-range chemical stimuli. Inside acceptable hosts they produce aggregation pheromones that attract additional attackers. In a recent field experiment we induced defense responses in 60-year-old Norway spruce trees and monitored colonization by the spruce bark beetle Ips typographus. Induced stem sections had significantly less beetle colonization than control sections, with shorter parental galleries and fewer eggs deposited. In addition, fewer beetles were attracted to beetles tunnelling in induced bark. This reduced ability to attract conspecifics suggests that induced host defenses interfere with beetle pheromone production or emission. The mechanisms responsible for this are unknown, but may involve emission of volatile terpenes such as (E)-b-farnesene and linalool, which have been shown to increase up to 100-fold in induced Norway spruce trees. These compounds have been reported to attract natural enemies of herbivores or repel herbivores directly in other conifer-insect interactions.
Forfattere
Leif Sundheim May Bente Brurberg Trond Hofsvang Christer Magnusson Trond Rafoss Brita Toppe Anne Marte Tronsmo Bjørn ØklandSammendrag
Wild oats (A. fatua) is present in 155 out of 431 Norwegian municipalities. It is widely distributed in all municipalities in the main agricultural areas in south-east and central-east Norway, and in the municipalities close to the Trondheim fjord. Otherwise wild oats is present in only a few scattered municipalities not geographically connected to these main areas. Endangered area, not yet infested by A. fatua, is estimated to 228858 ha. This area is spread over the cereal growing part of Norway. The counties of North- and South -Trøndelag have a higher portion of endangered area not yet infested than south and central part of East Norway. The probability of entry of A. fatua from outside the PRA area (Norway) is very low. The probability of spread within Norway is high. In areas with low infestation, like in Trøndelag, the probability of spread is lower than in heavily infested areas. However, in areas with high level of infestation there are few new farms left to be infested. The official wild oats register is a valuable tool in regulations aiming to limit spread. The register also provides a tool to follow up infested farms. The register would be even more useful if inspection for infestation on new farms had been more systematic. Wild oats is no longer devastating even in cereal monocropping, due to cost efficient herbicides. However, in Norway an increasing area is infested with wild oats. The infestation may vary from only a few plants to total coverage of the field. In cereal monocropping chemical treatment with and without hand roguing is the only feasible control methods. Hand roguing alone is expensive and ineffective even on modest infestation. The structural changes in cereal farming result in more farms being managed by entrepreneurs. Field managed by entrepreneurs promotes use of herbicide even on small infestations since this is a cost effective measure to control the weed. Less official control of cereal fields can also be expected. The economical consequences are thus expected to be high. The economical consequences can be even higher in organic farming if the most profitable rotation has to be changed to a less profitable one because of wild oats infestation.
Forfattere
Leif Sundheim May Bente Brurberg Trond Hofsvang Christer Magnusson Trond Rafoss Brita Toppe Anne Marte Tronsmo Bjørn ØklandSammendrag
The main Avena species that are important weeds of cereal and arable crops include A. fatua L., A. sterilis and A. barbata Pott. All three species have an abscission scar on the grains. A risk assessment of A. fatua L. as an indirect pest in Norway is given in a separate document. For both A. sterilis ssp. macrocarpa and ssp. maxima, and for A. barbata Pott, the potential for entry and establishment in Norway is considered as very low. A. sterilis ssp. ludoviciana (winter wild oats) has a moderate potential for establishment in Norway. The suitability of the environment for A. sterilis ssp. ludoviciana was therefore investigated: Our assessment of the probability of establishment indicates that the climate is not favourable for establishment of A. sterilis ssp. ludoviciana in Norway. A. sterilis ssp. ludoviciana is a problem in southern Europe and central southern England and is mainly a weed in winter cereals. While it is highly likely that the probability of establishment of A. sterilis ssp. ludoviciana has increased in Norway in recent years due to climate change and consequent changes in cultural practices, its probability of establishment in Norway is still low and it is therefore not likely that it will become a weed in Norway under current conditions. However, if the future climate of the PRA area changes, so that winter conditions become similar to conditions in southern England, while the acreage of winter cereal continues to grow, A. sterilis ssp. ludoviciana could become a weed in Norway. A. sterilis ssp. ludoviciana is not present in Denmark where winter cereals are much more widely cultivated, and the climate is more favourable than in Norway. One would therefore expect the weed to establish in Denmark before it will become a problem in Norway
Forfattere
Leif Sundheim May Bente Brurberg Trond Hofsvang Christer Magnusson Trond Rafoss Brita Toppe Anne Marte Tronsmo Bjørn ØklandSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Hui Liu Sarah J. Coulthurst Leighton Pritchard Peter E. Hedley Michael Ravensdale Sonia Humphris Tom Burr Gunnhild Takle May Bente Brurberg Paul R.J. Birch George P.C. Salmond Ian K. TothSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Rotstokkråte i jordbær og rød rotråte i bringebær kan gi store avlingstap. En effektiv måte å kontrollere sykdommene på er bruk av resistente sorter. Sortsforedling er både tids- og arbeidskrevende, men ved bruk av bioteknologiske verktøy kan prosessen rasjonaliseres. Bioteknologiske verktøy er også meget godt egnet for å få detaljert kunnskap om samspillet mellom en plante og en skadegjører, hvilket på sikt kan gi nye metoder for bekjempelse.