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
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Sammendrag
The leaf blotch complex is one of the most important yield limiting disease on wheat in Norway. It is caused by three pathogens, Septoria tritici ( Mycosphaerella graminicola), Stagonospora nodorum ( Phaeosphaeria nodorum), and Drechslera tritici-repentis (Pyrenophora tritici-repentis). The symptoms of each of the pathogens are similar and easily confused with leaf senescence, making it difficult to assess the true disease severity and thus hampering breeding for leaf blotch resistance. To reduce unnecessary pesticide use and the risk of pesticide resistance developing in the fungal populations, timing of disease control measures are based on forecasting models. The degree of a leaf blotch epidemic is determined by initial inoculums, precipitation, temperature, time, availability of susceptible hosts and the degree of susceptibility. During the last 20 years, the start of the growing season as marked by a soil temperature of 5C, has advanced by 1-1.5 days per year (Rafoss, 2009), indicating an increase in the length of growing seasons. The trend for warmer and wetter growing seasons is predicted to continue in the future. It is of high relevance to the wheat industry to understand the impact of these changes on leaf blotch diseases in the field to optimize disease forecasting and management. We have collected data on leaf blotch severity in the field and weather conditions at different wheat growing areas in Norway over the last 10 years. Based on this data, we do not see a general increase in disease severity over the last decade. However, the data shows that there are local shifts in maximum disease severity; areas that support high disease severity and areas that support very little. Given the amount of initial inoculum and availability of susceptible hosts are comparable between the different wheat growing areas, the local climate per site becomes the determining factor for the epidemic. We studied the effect of relatively small, local differences in precipitation, temperature, and start of growing season on leaf blotch development in the field. The analysis of local shifts in climatic conditions and their relation to disease development allows us to estimate the effect of the changing climate on leaf blotch disease in the future.
Sammendrag
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Sammendrag
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Sammendrag
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Forfattere
Kjell Andreassen Volkmar Timmermann Nicholas Clarke Halvor Solheim Ingvald Røsberg Wenche AasSammendrag
Helsetilstanden hos bartrær må betegnes som tilfredsstillende, men hos gran ble det observert en del toppskranting og avdøing i hogstklasse 3 og 4. Vi registrerte få insekt- og soppskader på gran der 0,4% av trærne var skadet, mens 1,5% av furutrærne hadde slike biotiske skader. Antall nye toppbrekk, vindfall og andre snø- og vindrelaterte skader var omtrent på samme nivå som tidligere i overvåkingsperioden. Kronetettheten utviklet seg positivt for treslagene gran, furu og bjørk i 2009, selv om bjørk fortsatt har lav gjennomsnittelig kronetetthet. Kronefargen utviklet seg også positivt for bartrærne med 1,6% flere gran- og 5,5% flere furutrær med frisk kronefarge i 2009 enn i 2008. For bjørk ble det derimot registrert 1% færre trær med frisk grønn farge. Det er de eldste trærne som er mest utsatt for kroneutglisning og misfarging. Helsetilstanden til trær, registrert ved kronetetthet, misfarging og skader, påvirkes i stor grad direkte av værforhold som tørke, frost og vind, eller indirekte ved at været påvirker omfanget av soppsykdommer og insektangrep. Langtransporterte luftforurensninger kan komme i tillegg til eller virke sammen med klimatiske forhold.....
Forfattere
Dag-Ragnar Blystad Karen Rae Bone May Bente Brurberg Erling Fløistad Roar Moe Arild Sletten D. L. Davies Carl Jonas Jorge Spetz Sonja KlemsdalSammendrag
We have beendoing research on two phytoplasma diseases relevant for Norwegian plantproduction. Theoccurrence of Apple proliferation phytoplasma in NorwayOurinstitute was made aware of suspicious symptoms in 1996. A few trees of apple‘Summerred’ in Gvarv, Telmark County, had symptoms looking like appleproliferation. This case initiated a survey. The first samples were analyzed inEngland. Later we have done the PCR-diagnosis in our own lab.During asurvey carried out from 1996 to 1998, Apple proliferation was found in 14orchards: 1 experimental orchard inTelemark County, 4 orchards in Vestfold County, 4 orchards in Hordaland Countyand 5 orchards in the County of Sogn og Fjordane.Appleproliferation has later also been found at other locations. From this we canconclude that this quarantine disease is found in almost all importantfruit-producing districts. It is important to follow the situation to stopfurther spread of this disease. All infected trees have been eradicated.Theamount and distribution of Poinsettia branch-inducing phytoplasma in poinsettiaFree-branchingpoinsettias (Euphorbia pulcherrima) were first introduced during the sixties throughthe Norwegian cultivar ‘Annette Hegg’. The identity of the “branching agent”,was proven to be a phytoplasma, termed Poinsettia branch-inducing phytoplasma(PoiBI) (Lee et al. Int. Journal of Syst. Bacteriology 48,1153-1169.1998).Without phytoplasma, poinsettias grow tall, and produce very few branches.We havestudied the relative amount and distribution of PoiBI in poinsettia and howthis relates to branching in different cultivars grown under different lightlevels and temperatures using a quantitative PCR assay (TaqMan). Results fromthis work were presented.
Sammendrag
VKM"s Panel 9 gives the following main conclusions of part 2 of the risk assessment: 1) Under the present climatic conditions, and if no control measures are taken, an introduction of PWN to the PRA area will not cause increased pine tree mortality. The level of uncertainty of this assessment is low. 2) Assuming the IS92a climate change scenario for the period 2000-2049 (RegClim), which involves a ~2 ºC temperature increase by the end of the period, an introduction of PWN to the PRA area will, if no control measures are taken, cause a minor increase in pine tree mortality (300 trees per year on average). The mortality can become larger if the temperature increases more than 2 ºC, and will gradually increase with time after 2049 due to spread of PWN. The level of uncertainty of these assessments is medium to high. 3) Any effects of PWN presence in the PRA area on export of wood and wood products will be of little importance. The level uncertainty of this assessment is low. 4) It will be almost impossible to eradicate PWN once it has been introduced to the PRA area. The level of uncertainty of this assessment is low. 5) The cost of a single eradication event as described in the preliminary contingency plan for the PRA area is approximately 700 mill. NOK. Due to expected spread, the total cost of eradication attempts following one introduction event will be approximately 2000 mill. NOK for the first 50 years. The level of uncertainty of these assessments is medium. 6) The negative effects of the control measures on the environment will be major. The level of uncertainty of this assessment is low.