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
Seasonal production of spores (conidia) of Monilinia laxa (Aderh. & Ruhl) Honey on overwintering mummified fruits, blighted flowers and fruit spurs, and newly infected flowers of sweet cherry (Prunus avium L.) was investigated in Norway in 1997-1999. Infected plant parts were incubated in saturated air for 48 h prior to washing in distilled water, followed by a quantification of conidia from the spore suspensions with a light microscope. Mummified fruits or fruit spurs containing blighted flower and leaf parts, placed on the ground in the spring or the preceding autumn, more quickly depleted their inoculum compared to similar plant parts still hanging in trees. Conidia were produced in high numbers on mummified fruits left hanging in trees for 2-3 years after infection. In 1997, the conidial production on fruit mummies in trees was relatively even during the growing season. The year after, the highest sporulation on mummified fruits in trees occurred prior to flowering, and by harvest the sporulation was reduced by 92%. The wet weather that occurred in 1998 probably depleted the inoculum earlier than in 1997, when the summer was drier. The major production of conidia from fruit spurs occurred prior to or around bloom, and very few conidia were observed at harvest. Infected flower and leaf parts attached to the overwintering fruit spurs contained higher numbers of conidia than the fruit spurs themselves. Flowers infected in the spring produced most conidia during the first two months after infection, however, if remaining attached to the fruit spurs, they produced conidia during the entire season. Infected overwintered flowers produced 3-10% as many conidia as newly infected flowers in May and early June. The maximum production of conidia from single overwintered mummified fruits was more than 10 times the conidial production from an overwintered fruit spur or newly infected flower at their respective times of peak sporulation
Sammendrag
Three copper fungicides were tested in their effect against apple scab (Venturia inaequalis). Copper oxide and Copper oxychloride were the most effective against scab. Copper hydroxide was the least phytotoxic to apple foliage and fruit
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.
Sammendrag
The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum (atroviride) P1 to suppress Botrytis cinerea was investigated in laboratory, greenhouse, and field trials. Preliminary nutrient activation at 21°C accelerated subsequent germination of the antagonist at temperatures from 9 to 21°C; at >18°C, the germination time of preactivated T. harzianum P1 conidia did not differ significantly from that of B. cinerea. When coinoculated with B. cinerea, concentrated inocula of preactivated but ungerminated T. harzianum P1 conidia reduced in vitro germination of the pathogen by >87% at 12 to 25°C; initially quiescent conidia achieved this level of suppression only at 25°C. Application of quiescent T. harzianum P1 conidia to detached strawberry flowers in moist chambers reduced infection by B. cinerea by >85% at 24°C, but only by 35% at 12°C. Preactivated conidia reduced infection by >60% at 12°C. Both quiescent and preactivated conidia significantly reduced latent infection in greenhouse-grown strawberries at a mean temperature of 19°C, whereas only preactivated conidia were effective in the field at a mean temperature of 14°C on the day of treatment application. An antagonistic mechanism based on initiation of germination in sufficiently concentrated inocula suggests that at suboptimal temperatures the efficacy of Trichoderma antagonists might be improved by conidia activation prior to application
Sammendrag
Anthracnose caused by Colletotrichum acutatum J.H. Simmonds was detected in strawberry (Fragaria x ananassa Duch.) for the first time in Norway in 1999. Symptoms were found in greenhouse grown strawberries in the cultivar Korona. The article describes symptoms, identification, fungal characteristiques, and how Koch"s postulate was fulfilled
Sammendrag
Artikkelen gir et kort sammendrag av resultater fra forsøk med bruk av undervarme og nyttesopp som tiltak mot råtesopper i jordbær. Råtesoppene trenger fuktighet for infeksjon og sjukdomsutvikling. Varmerør under plantene har redusert luftfuktigheten og med det betydelig redusert faren for angrep av råtesopper. Ved å bruke nyttesoppen Trichoderma harzianum mot gråskimmelsoppen (Botrytis cinerea), er antallet råtne bær blitt ytterligere redusert
Sammendrag
Det vert rapportert frå felt- og laboratorieforsøk med bekjemping av gråskimmel (Botrytis cinerea) i jordbær ved hjelp av nyttesoppane Trichoderma harzianum og Gliocladium roseum. Jamt over var det for dårleg verknad av nyttesoppane til at dei kan tilrådast i kommersiell bruk i dag. Det var lovande effekt av forbehandling av soppsporer frå T. harzianum. Dette vil verta vidare prøvd ut i forsøk.
Forfattere
Hans StabbetorpSammendrag
Artikkelen gir en kortfattet oversikt over den forskningsinnsats som er g jort og gjøres for å redusere avrenning av jord og plantenæringsstoffer fra landbruket i Norge. Omtaler også de viktigste resultatene fra dette arbeidet
Forfattere
Hans StabbetorpSammendrag
Artikkelen gir en oversikt over arealbruken og avlingsutviklingen i korn og oljevekster og ser på mulighetene framover. Det er viktig å opprettholde arealene av hvete. Det forventes en stor og relativ rask økning av oljevekstarealene, og det vil være aktuelt å starte produksjon av erter
Forfattere
Arild SlettenSammendrag
EPPO (European and Mediterranean Plant Protection Organization) ble stiftet i 1951. I forbindelse med 50-års jubileet i 2001 ble det arrangert en konferanse hvor sentrale deler av organisasjonens virksomhet ble presentert. EPPO opprettet i 1987 et panel som fikk i oppdrag å vurdere betydningen av, og å komme med anbefalinger om bekjempelsen av farlige plantepatogene bakterier som var oppført på organisisasjonens A1 og A2-liste over karanteneskadegjørere. Panelet har vært sammensatt av bakteriologer fra 12 av EPPOs medlemsland. De har hatt årlige møter, og har vurdert og gitt anbefalinger om fytosanitær status og særskilte karantenetiltak for 23 plantepatogene bakterier til EPPOs styrende organer. Panelet har gitt et vesentlig bidrag til forståelsen av betydningen av bakterier som karanteneskadegjørere på planter, og hvordan de kan bli bekjempet og utryddet. Panelt har også vært et viktig forum for diskusjon og utveksling av erfaring om slike bakterier mellom eksperter fra forskjellige deler av Europa. Det er blitt bygget nettverk mellom forskere, som også har resultert i felles forskningsprosjekter