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.
2001
Sammendrag
The present paper presents a summary of the most recent work on climatological conditions affecting ascospore discharge in Venturia inaequalis, the apple scab fungus, carried out at our two institutes. Experiments were performed under laboratory conditions by means of a wind tunnel and in the field using volumetric spore traps, either with artificial irrigation or under natural rain. One purpose of the studies was to reveal artificial laboratory conditions that could affect suppression of ascospore release normally observed under orchard conditions. Both air containing low relative humidity passing over leaf samples during simulated rain and extended maturation of the pseudothecial populations increased the number of spores released during darkness. These factors can thus explain some of the discrepancy between previously reported lab and field results. Field experiments with artificial irrigation showed that the possibility of high ascospore release during darkness increased once 80% or more of the season"s ascosporic inoculum had matured. The earlier observation of the stimulating effect red light has on ascospore release was confirmed. Under lab conditions, light intensities similar to what was recorded in the field around sunrise on rainy days, stimulated ascospore release. The rate of discharge increased with increasing light intensities up to a level normally occurring 2-3 hours after sunrise. When leaf samples were exposed to light and simulated rain in the lab, the rate of release increased over time. Thus, the delay in reaching the peak rate of ascospore release after sunrise may be due to the combined impact of increasing light intensity after sunrise and the intrinsic increase in rate of release over time. Ascospore release was monitored in the wind tunnel at temperatures of 1-8°C in daylight-balanced light. Low temperatures resulted in a lag phase in the cumulative distribution of ascospore release, where few or no ascospores were detected. The time until first detection of a given quantity of inoculum was inversely proportional to temperature. There was a reduction in the rate of release from 8 to 1°C, and consequently there was a reduction in the number of ascospores released at any given time. Where temperatures below 10°C coincided with continious rain and leaf wetness during night and day in field studies in Norway, few ascospores were released until 4-5 hours after sunrise. High quantities of ascospores were recorded during nights with dew in two Norwegian orchards. Episodes where more than 1% of the season"s inoculum was released during dew occurred around bloom of apple, and followed more than 2 days of fair weather (clear, warm days and cool, humid nights). Field studies showed that protracted dry periods with no or little rain not only delayed ascospore release, but also maturation, and consequently extended the season for ascospore release. Recommendations for management of the apple scab fungus are discussed.
Forfattere
Celine Rebours Chantal Billard Joel CossonSammendrag
Det er ikke registrert sammendrag
Forfattere
Celine Rebours Chantal Billard Joel CossonSammendrag
Det er ikke registrert sammendrag
Forfattere
Helge BonesmoSammendrag
Styrkar Foss fra Rennebu fikk nylig en påskjønnelse fra Arild Larsen, Planteforsk, for sitt arbeid med å dyrke fram den nye engrapp-sorten "Knut". "Knut" vil fra 2004 være en aktuell sort for hele Trøndelag.
Sammendrag
Rapporten beskriver resultatene fra søyleforsøk i klimaregulert rom hvor filtermaterialene skjellsand, Leca lettklinker og perlitt ble undersøkt i en periode på 200 dager. Korngraderingen var relativ lik og tilsvarte grovsand. Forsøket ble belastet med slamavskilt husholdningsavløp. Den hydrauliske belastningen var 400 og 600 l/m2?d. Vannet ble tilført søylene med peristralpumpe hvert 30. minutt. Formålet med laboratorieforsøket har vært å finne forfiltermedier som fungerer tilfredsstillende ved høye belastninger, både hydraulisk og rensemessig. Resultatene viser at det ikke var noen vesentlig forskjell i resultatene mellom de tre ulike filtermediene. Renseevne var følgende: SS 90%, organisk stoff (BOF, TOC) 75-80%, total nitrogen 5-10%, nitrifikasjon 75 85% etter 4 uker, total fosfor 30 70% (avtakende mot slutten). Forsøket indikerer at dersom det oppnås en jevn fordeling av avløpsvannet på filterflaten av et porøst filtermedium tilsvarende fingrus og det benyttes en utjevningstank med støtbelaster og programmerbar logisk styring (PLS) så kan filteret belastes opp til 400-600 l/m2?d i kortere perioder (inntil 180 dager i året). Forsøket er gjennomført under relativt ideelle forhold i et forsøkslaboratorium uten variasjon i f.eks. temperatur (9ºC) og størrelse på dosene. Ved overføring av resultatene til fullskala filteranlegg anbefales det inntil videre at den hydrauliske belastningen maksimalt er 300 500 l/m2?d dersom formålet er god BOF reduksjon (>75%) og høy nitrifikasjon. Kompakte forfiltre med støtbelastning kan benyttes til forbehandling før infiltrasjon, våtmarksfilter eller som eget biologisk rensetrinn.
Sammendrag
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Forfattere
Lars SekseSammendrag
The paper summarises a business meeting of the Working Group F14 Cherry Production under the Fruit Section in the International Society of Horticultural Science (ISHS) held during the Fourth International Cherry Symposium in Oregon and Washington, USA on June 24-29 2001. Gregory Lang, Michigan State University, USA was elected new chair of the working group susseeding Lars Sekse, and the Uludag University, Turkey was suggested as host for the next symposium in 2005.
Sammendrag
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Sammendrag
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Forfattere
Tore SkrøppaSammendrag
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