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
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Dag-Ragnar Blystad jihong liu clarke Sissel Haugslien Merete Wiken Dees Erling Fløistad Shaochen Xing Carl Jonas Jorge SpetzSammendrag
Virus og fytoplasma i julestjerne har vært et forskningsfelt ved Bioforsk Plantehelse siden 1990-tallet. Vi har kombinert dette med ny kunnskap om gen-transformering. I 2009, etter flere års FoU-arbeid, er vi kommet så langt at vi har dyrket virusresistent julestjerne i et mindre forsøk i et gartneri. Nå er det naturlig å summere opp resultater vi har oppnådd og muligheter som åpner seg.
Forfattere
Håvard Eikemo David M. Gadoury Robert A. Spotts Oscar Villalta Piet Creemers Arne StensvandSammendrag
Estimates of ascospore maturity generated by models developed for Venturia pirina in Victoria, Australia (V-NV, V-SV), Oregon, USA (S), or for Venturia inaequalis in New Hampshire, USA (NH-1 and NH-2) were compared to observed ascospore release of V. pirina in 21 site/yr combinations. When plotted against degree-days, the lag phase and slope of all model estimates differed from observed release. The S model and V-SV model fit well with the data from Southern Victoria, while the data from Norway, Belgium and most years from Northern Victoria show a lag phase in the beginning of the season that was not present in the two models. In particular, data from the high-rainfall region of southern Victoria showed more variation between years than the other sites. Identifying the precise biofix (bud break) to initiate degree-day accumulation for the NH-2 model was problematic at both Australian sites, as regions with warm winters and minimal chilling exhibit protracted bud break. Linear regressions generated similar R2 values for the various models in many cases, but where differences were noted they more often favored the most recent model developed for V. inaequalis (NH-2). The NH-2 model also provided the most accurate estimates of 95% ascospore depletion (a key event in many disease management programs) for Norway, Belgium, and the higher rainfall areas of southern Victoria. Although developed for use in management of apple scab, the NH-2 model appears a reasonably accurate tool for predicting the release of ascospores by the pear scab pathogen, in particular in regions with moderate rainfall and colder winters.
Sammendrag
Most fungicide applications targeting apple scab aim to control primary infections caused by ascospores and spraying is thereby linked to ascospore availability. We investigated the effect of pre bud break climatic conditions on seasonal patterns of ascospore release. Apple leaves bearing pseudothecia of Venturia inaequalis were overwintered at orchard sites in 8 countries for up to 3 years. Leaf samples were collected 2 to 5 weeks before bud break and again at bud break, air dried, and sent via airmail to Norway. The samples were stored at -18ºC upon arrival until tested. Disks cut from each replicate leaf sample were incubated moist at 20ºC to allow ascospore maturation but prevent discharge. Matured ascospores were induced to discharge twice a week and enumerated until the supply was exhausted. The proportion of ascospores ejected was fitted against degree-day accumulation using logistic regression. The regression intercept (onset maturation), slope (maturation rate), as well as the absolute number of spores counted differed significantly (P< 0.001, P = 0.05, P< 0.001 respectively) among sites and sampling dates. There was a significant interaction between site and sampling date, indicating that climatic conditions prior to bud break differentially impacted the subsequent ascospore availability. Observed differences could perhaps be used to further refine previously described models of ascospore maturity.
Sammendrag
Sprøyting basert på modellar som varslar fare for infeksjon av gråskimmel i jordbær, har vore samanlikna med rutinesprøyting over fleire år. Resultata viser at sprøyting etter varsel gir færre sprøytingar og kan gi god effekt, men ved for lange sprøyteintervall vil det vera fornuftig å leggja inn ekstra sprøytingar.
Sammendrag
Development of ontogenic resistance to powdery mildew (Podosphaera aphanis) on strawberry leaves has been reported, however, the components of resistance have not been elucidated. Five developmental stages of strawberry leaves were identified and assigned numerical values from newly emerged and unexpanded (S1) to fully expanded and dark green (S5) of cvs. Korona and Senga Sengana. The upper and lower surface of the leaves were inoculated from each of the five leaf developmental stages and incubated under controlled conditions. The effect of leaf age on germination, infection efficiency, latency period, and sporulation were later evaluated. All responses were significantly (p = 0.05) affected by leaf age. Germination percentage, infection efficiency, and sporulation were highest, and latent periods were shortest on S1 leaves of both cultivars. On Senga Sengana, germinating conidia produced fewer secondary hyphae during infection. Conidia produced very few secondary hyphae and did not sporulate on S3 leaves, and no infections established on S4 or S5 leaves. The high success of infection and colonization of P. aphanis on S1 leaves indicates that disease is established preferentially on emergent and expanding leaves and these should be the target of management strategies.
Forfattere
David M. Gadoury Belachew Asalf Tadesse M Heidenreich Maria Herrero MJ Welser Robert C Seem Anne Marte Tronsmo Arne StensvandSammendrag
A collection of four clonal isolates of Podosphaera aphanis was heterothallic and was composed of two mutually exclusive mating types. Cleistothecial initials approximate to 20 to 30 mu m in diameter were observed within 7 to 14 days after pairing of compatible isolates and developed into morphologically mature ascocarps within 4 weeks after initiation on both potted plants maintained in isolation and in field plantings in New York State and southern Norway. Ascospores progressed through a lengthy maturation process over winter, during which (i) the conspicuous epiplasm of the ascus was absorbed; (ii) the osmotic potential of the ascospore cytoplasm increased, resulting in bursting of prematurely freed spores in water; and, finally, (iii) resulting in the development of physiologically mature, germinable, and infectious ascospores. Release of overwintered ascospores from field collections was coincident with renewed plant growth in spring. Overwintered cleistothecia readily dehisced when wetted and released ascospores onto glass slides, detached strawberry leaves, and leaves of potted plants. Plant material exposed to discharged ascospores developed macroscopically visible mildew colonies within 7 to 10 days while noninoculated controls remained mildew free. Scanning electron and light microscopy revealed that cleistothecia of P. aphanis were enmeshed within a dense mat of hyphae on the persistent leaves of field-grown strawberry plants and were highly resistant to removal by rain while these leaves remained alive. In contrast, morphologically mature cleistothecia on leaves of nine deciduous perennial plant species were readily detached by simulated rain and seemed adapted for passive dispersal by rain to other substrates. Contrary to many previous reports, cleistothecia appear to be a functional source of primary inoculum for strawberry powdery mildew. Furthermore, they differ substantially from cleistothecia of powdery mildews of many deciduous perennial plants in their propensity to remain attached to the persistent leaves of their host during the intercrop period.
Sammendrag
Insektene er blant de organismene som reagerer raskest på klimaendringer. De har kort generasjonstid, er svært mobile og utviklingshastigheten deres er direkte påvirket av temperaturen. Dette betyr at utviklingen fra egg til voksent insekt går raskere når temperaturen øker, noe som kan få store praktiske konsekvenser for skogbruket.
Sammendrag
Artikkelen presenterer prosjektet VEKSTHUS 2009-2012: Veksthusnæringen ønsker, og bidrar finansielt sammen med Norges Forskningsråd til, å utvikle seg mot en mer miljøvennlig produksjon. Mulighetene for å spare energi og øke plantekvaliteten ved å tillate større temperaturvariasjoner og bruke nye lyskilder og dekkematerialer blir undersøkt i dette prosjektet. Samtidig ser vi på hvordan ulike belysningsmetoder vil virke inn på bekjempelse av mjøldogg og biologisk bekjempelse av skadedyr.