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.
2010
Forfattere
Nina Johansen Solveig Haukeland Arnstein Staverløkk Anette Sundbye Kari-Ann Strandenæs Toril SagenSammendrag
Rovmidden Neoseiulus californicus, rovtegen Orius laevigatus og nyttenematoden Heterorhabditis bacteriophora ble brukt til biologisk bekjempelse i Norge inntil 2001, da den nye godkjenningsordningen for nyttedyr trådte i kraft. Godkjenning av disse 3 artene ble avslått fordi man manglet informasjon om forekomst, kuldetoleranse, overvintringsevne og etableringspotensial i Norge. For å skaffe slik informasjon ble en kartlegging av forekomsten av de tre artene Norge startet i 2007, og videreført i 2009. Orius laevigatus og H. bacteriophora ble funnet i kartleggingsundersøkelsen. 2 individer av N. californicus ble funnet på planter på en komposthaug utenfor et veksthus i Trøndelag i 2007. Dette veksthuset har hatt en permanent egen stamme av denne rovmidden. Det ble gjort nærmere undersøkelse utenfor dette veksthuset i 2009, men da ble arten ikke funnet. Det er derfor lite sannsynlig at noen av de 3 artene har etablert seg her i Norge. Det ble også utført overvintringsforsøk med N. californicus og O. laevigatus fra kommersielle nyttedyrpreparater. Forsøkene ble utført på friland på Ås i Akershus fra august 2009 til april 2010. Verken rovmidden eller rovtegene viste tydelige tegn til å gå i diapause utover høsten. Noen få levende rovmidd og rovteger ble funnet i november, men ingen rovmidd eller rovteger overlevde fram til januar. Tidligere overvintrings- og kuldetoleranseforsøk utført på Ås og Lillestrøm med de samme nyttedyrpreparatene viste også lav kuldetoleranse hos N. californicus og O. laevigatus. En vurdering av etableringspotensial i Norge for de to artene er gjort på grunnlag av tilgjengelig informasjon om naturlig utbredelse, diapause, kuldetoleranse og overvintringsevne hos de 2 artene og historisk temperaturdata for Ås og Lier (mildt innlandsklima) og Særheim (mildt kystklima). Per i dag er det lite sannsynlig at N. californicus kan etablere seg permanent i Norge. Det er lite sannsynlig at O. laevigatus kan etablere seg permanent i områder med tilsvarende klima som Ås og Lier, men det er risiko for etablering i områder med tilsvarende klima som Særheim.
Sammendrag
The pinewood nematode (PWN) is one of the worst tree-killing exotic pests in East-Asian countries. The first European record of establishment in Portugal in 1999 triggered extensive surveys and contingency plans for eradication in European countries, including immediate removal of large areas of conifer host trees. Using Norway as an example, we applied a simulation model to evaluate the chance of successful eradication of a hypothetical introduction by the current contingency plan in a northern area where wilting symptoms are not expected to occur. Despite a highly variable spread of nematode infestations in space and time, the probability of successful eradication in 20 years was consistently low (mean 0.035, SE 0.02). The low success did not change significantly by varying the biological parameters in sensitivity analyses (SA), probably due to the late detection of infestations by the survey (mean 14.3 years). SA revealed a strong influence of management parameters. However, a high probability of eradication required unrealistic measures: achieving an eradication probability of 0.99 in 20 years required 10,000 survey samples per year and a host tree removal radius of 8,000 m around each detection point.
Forfattere
Arne Stensvand Belachew Asalf Håvard Eikemo Andrew Dobson Anne Marte Tronsmo David M. Gadoury Robert C. SeemSammendrag
Denne artikkelen omhandlar resultat frå prøving av ulike alternative middel mot jordbærmjøldogg. Forsøka vart gjort i laboratorium, veksthus og plasttunnel.
Forfattere
David M Gadoury Arne Stensvand Robert C. Seem Catherine Heidenreich Maria Herrero Mary Jean Welser Andrew Dobson Håvard Eikemo Belachew AsalfSammendrag
Cleistothecia on leaves of deciduous perennials are often dispersed before leaf fall to other substrates. In contrast, strawberry leaves remain attached during winter, and cleistothecia of Podosphaera macularis remained attached to these leaves. Release of overwintered ascospores was coincident with renewed plant growth, and pathogenicity of ascospores was confirmed. Upper and lower surfaces of emergent leaves were similarly susceptible, but upper surfaces were obscured by folding in emergent leaves. Emergent leaves exposed to airborne inoculum developed severe infection of the lower surface, but not the obscured upper surface. Emergent leaves acquired ontogenic resistance during unfolding, and the upper leaf surface thereby escaped infection. We found no evidence that the pathogen survives winters in New York, USA or Norway within crown tissue. Plants stripped of infected leaves remained mildew-free when forced after overwintering, while mildew colonies commonly developed on emergent leaves of plants not stripped of mildewed leaves. Unsprayed plots established using mildew-free plants either remained asymptomatic or developed only traces of powdery mildew during one growing season, even when located within 100 to 150 meters of severely diseased plots. In summary, our results suggest the following: (i) sanitation, use of disease-free plants, and eradicative treatments could contribute greatly to management of strawberry powdery mildew; (ii) cleistothecia represent a functional source of primary inoculum; and (iii) the common observation of higher mildew severity on lower leaf surfaces may reflect escape of the upper epidermis due to the combined effect of leaf folding and rapid acquisition of ontogenic resistance.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Rotkjuke, Heterobasidion annosum s.l. er et stort problem i de nordlige barskogsområder. I Norge er hele 20 prosent av grantrærne angrepet av denne skadesoppen. Dette fører ikke bare til at tømmeret blir ubrukelig til de fleste formål, men også til frigjøring av mye CO2 som ellers ville vært bundet i trærne. Rotkjuka angriper via rotkontakter. Dette skjer ofte via stubber av felte nabotrær etter hogst eller tynning. Soppen ødelegger stammen opp til tolv meter fra bakkenivå.
Sammendrag
Foredrag om varslingsmodeller for DON i hvete og havre
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Organic fields are often assumed to have fewer pests and more beneficials than conventionally managed fields. We monitored 12 Norwegian strawberry fields, 6 organic and 6 conventional fields, by sampling leaves twice a year in 2002 and 2003. Young folded leaflets were visually inspected for eggs and adult females of strawberry mite (Phytonemus pallidus fragariae), and mature leaves were used for extraction of mobile stages of two-spotted spider mite (Tetranychus urticae). The spider mites were examined for infection of the mite-pathogenic fungus Neozygites floridana. Predatory mites (Phytoseiidae) were recorded on both leaf types, and the females mounted and identified. We also sampled leaves from selected plants in the boundary vegetation of most fields to look for sources of T. urticae, phytoseiids and N. floridana. Soil was sampled from each field, to study the natural occurrence of entomopathogenic nematodes. All samples were taken 0-13 metres from the border vegetation. Both pest mites tended to be more abundant in conventional than in organic fields, while the number of phytoseiid mites was very low in both growing systems. Nevertheless, three phytoseiid species were recorded for the first time in Norway: Amblyseius rademacheri Dosse, Neoseiulus kodryensis (Kolodochka) and Neoseiulus reductus (Wainstein). N. floridana infection found in T. urticae females varied from 0-19%, and was higher in 2002 than in 2003. The fungus was recorded at least once in all 12 fields, and there was no consistent difference between the two growing systems. In 2002 there was a significant negative correlation between % T. urticae with N. floridana hyphal bodies found in the first sampling and the number of T. urticae present in the second sampling about 4 weeks later. Beneficial nematodes (mostly Steinernema) tended to occur in more of the organic than of the conventional soil samples. To sum up, both pests (T. urticae and P. pallidus) and one of the beneficial groups (entomopathogenic nematodes) seemed to conform to the expected difference between organic and conventional fields. There are many possible mechanisms related to the differences in pesticide and fertilization regimes that could lead to such a pattern. For the two remaining beneficials (N. floridana and Phytoseiidae) we could not find a consistent correlation between abundance and growing system.
Sammendrag
Det er ikke registrert sammendrag