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
Sammendrag
Specific PCR primers were developed for identifying two post harvest pathogens, Mycocentrospora acerina and Fibularhizoctonia carotae, which cause liquorice rot and crater rot respectively, during prolonged low temperature storage of carrots. The methods allow routine detection of less than 0.3 pg of M. acerina DNA and less than 0.03 pg F. carotae DNA, even in the presence of large excess of plant or soil DNA. Standard PCR and quantitative PCR gave similar results and either method could be used in a practical situation. Experiments were carried out testing these methods on different types of carrot tissue- and soil- samples. Soil was sampled before sowing, and soil adhering to the roots or root tissue was sampled at different times during the growing season or at harvest. Soil adhering to the carrots at harvest had the best predictive ability for liquorice rot development during storage (R2predicted 74.9 % using standard PCR), but samples taken during the growing season also gave reasonably good predictive ability values. PCR data from soil samples taken in the spring were not as good as a predictor for thisdisease. A dense sampling strategy using 20 m between sampling points generally gave better orrelation between PCR data and disease data than using 40 m between the sampling points. Use of the developed methods in an IPM strategy for liquorice rot is discussed. For crater rot the correlation between PCR data and disease data was generally poor for all types of samples. These results are discussed in relation to the biology of F.carotae.
Forfattere
Lars Tørres HavstadSammendrag
During 2009-10 the effect of various harvesting methods on seed yield and seed quality were examined in crops of timothy (two trials) and red clover (one trial). Treatments included different dates of swathing and direct harvesting in both species. In timothy, swathing 7-8 days before combining was found to be an acceptable alternative to direct combining (double threshing), which has been the common harvesting method in Norwegian timothy seed production since the 1960ies. Optimal timing for swathing was when the seed water content (SWC) had dropped to 40-45 %. When swathing was done too early (SMC at 47%) the germination capacity was reduced, while a too late swathing date (SMC less than 35 %) increased seed shattering and reduced seed yield. Swathing before combining normally increase the capacity and efficiency of the combine harvester compared to direct combining. In addition, seed harvested from swathed windrows contain less water than directly harvested seed, which may decrease the seed drying costs. In red clover, swathing before combining was not beneficial, either with regard to seed yield or seed quality, compared to direct combining of crops being matured naturally or after desiccation with Reglone. The highest seed yield was harvested on plots being directly harvested when 80 per cent of the flower heads had naturally matured.
Forfattere
Lars Tørres HavstadSammendrag
Seed yield of perennial ryegrass normally decrease from the first to the second seed-harvesting year. In order to maintain a high seed yield in the second year crop different treatments in autumn / spring, after harvesting first year crop, were evaluated in two different series with Norwegian tetraploid forage-type cultivars of hybrid- and perennial ryegrass during 2006-2010. Treatments included nitrogen application (both series), treatments of straw (series 1) and regrowth (both series) and spraying against winter diseases (series 2). On average for three trials, straw chopping and spreading during the combining process reduced seed yield with 10 per cent compared to plots where straw had been removed. It is recommended to remove straw soon after harvest and keep stubble height during combining as low as possible. Except for one year (series 2), when the seed crops suffered from an early summer drought (poor utilization of applied spring nitrogen), it was not necessary to apply nitrogen in autumn in order to maximize seed yield. While removal of regrowth in autumn did not normally have any positive influence on the following years seed yield, the highest seed yield in one field was found on plots where regrowth had been cut to 5 cm and removed in early spring. Burning of stubble and regrowth in early spring may harm the plants and should be avoided. Plots being sprayed against winter diseases in late autumn (10 -20 October) produced the highest seed yields in series 2, and was economical beneficial, but further testing is necessary before recommendation for use in practical seed production.
Forfattere
Trond Hofsvang Ghislain Tepa-Yotto Ignace Godonou May-Guri SaethreSammendrag
The use of the aphid parasitoid Lysiphebus testaceipes in biological control.
Forfattere
Trond HofsvangSammendrag
Om marihøner som nyttedyr i hager.
Forfattere
Reidun Pommeresche Berit Swensen Øystein HaugerudSammendrag
Protozoer, eller dyreliknende protister, er organismer som består av bare en celle. De har en annen type kjerne enn bakterier, og mange av dem kan bevege seg ved hjelp av flageller eller cilier. Protozoer er mikroskopiske og de fleste er mellom 10 og 50 mikrometer i diameter. Enkelte arter kan bli helt opp til 1 mm store. De lever av bakterier, sopp, andre encella protister og ulike typer organisk materiale. Protozoer er dermed de minste «beitedyra» og «rovdyra» vi har i jorda.
Forfattere
Arne Fjellberg Arne FjellbergSammendrag
Spretthaler (Collemboler) er en gruppe med små dyr som lever i vegetasjonen, i strølaget og nedover i selve jorda til ca 15 cm dyp. De er viktige omdannere og nedbrytere av dødt plantemateriale og bidrar vesentlig til sirkulering av næringsstoffer. Navnet kommer av en «hoppegaffel» (furca) på bakkroppen. Denne er vanligvis foldet inn under dyret, men når den løses ut, spretter dyret opp i lufta og langt bortover bakken. Spretthalene kan hoppe mer enn 50 ganger sin egen kroppslengde i ett hopp.
Forfattere
Arild AndersenSammendrag
Different methods to reduce the population of Arion lusitanicus are being tested in private gardens already infested naturally with the slug, as well as in arenas in the laboratory. After the first 2 years out of a 4 year project the following preliminary trends have been observed: Untreated gardens had the highest populations. Gardens with owners trapping and killing slugs had the lowest populations. Gardens that were rearranged to become drier had intermediate populations. In arenas in the laboratory, slugs avoided cocoa chips mulch and alginate.
Forfattere
Arild AndersenSammendrag
Sixteen gardens in South-Eastern Norway were divided into four groups of four gardens. In treatment 1 (untreated control) nothing was done to reduce slug numbers. In treatment 2 ("killing") the owners were encouraged to collect and kill as many slugs as possible. In treatment 3 (habitat manipulation) owners were encouraged to change their garden so that an area of about 20 cm close to the ground was kept as open and dry as possible. Treatment 4 (extended habitat manipulation) included treatment 3 but also by removing of potential overwintering sites such as open compost, heap of stones etc. A reduction in the number of slugs was observed in all the years and in all treatments from June to September, probably due to natural mortality. The mean number of slugs was always lowest in treatment 2, in the third year showing a significant reduction of more than 80% from the control. In treatment 4 the mean reduction of slugs (not significant) was almost 40% during the third year. In treatment 3 the mean reduction (not significant) was about 55% during the third year. In conclusion, creating a garden not favorable to the Iberian slug can reduced the population without using molluscicides.
Forfattere
Arild AndersenSammendrag
The species richness of leafmining flies (Diptera: Agromyzidae) in four different environments were compared: Hay meadow, seashore meadows, biologically managed grass and conventionally managed grass. Hay meadows had the highest species richness, followed by seashore meadows, biologically managed grass fields and conventionally managed grass fields.