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.
2008
Forfattere
Arne HermansenSammendrag
Foliar diseases in potatoes
Sammendrag
Late blight forcasting in VIPS i s presented. Validation trials have show acceptable results regarding late blight control
Forfattere
Ragnhild Nærstad Vinh Hong Le Arne Hermansen Asko Hannukkala Bent J. Nielsen Jens Grønbech Hansen Lina Grönberg Björn Andersson Jonathan YuenSammendrag
A new potato late blight forecasting model based on hourly weather date is developed based on trials with spore traps and trap plants. The model is built up of sub models for for the different steps in the epidemiological cycle, spore production, release, survival and infection. Long humid periods are suitable for spore production, at moderate humidity the process goes slower. The amount of viable attached sporangia is reduced by drought, and some spores are washed off during rain. Spores are released into the air by a drop in humidity or increased radiation, but the release is inhibited at high leaf wetness. The amount of viable released spores is strongly inhibited by solar radiation. The spore load is also reduced by precipitation and by germination. The leaf wetness duration have to sufficient for the spores to germinate and infect. The risk of blight development is a function of the amount of viable released spores and the duration of leaf wetness.
Sammendrag
Sykdommen klumprot ble beskrevet som et problem allerede på 1200-tallet i Europa, og den er fortsatt et stort problem ved dyrking av korsblomstra vekster over hele verden. Årsak til sykdommen er parasitten Plasmodiophora brassicae som tidligere ble regnet som en sopp, men som etter nyere analysemetoder er definert til rike Protozoa. Parasitten angriper røttene på de fleste arter i korsblomstfamilien, både grønnsaker, prydplanter og viltvoksende planter inkludert en del ugras. Angrepet kan i enkelte tilfeller føre til tap av hele avlinger, og parasitten er meget vanskelig å bli kvitt hvis man først har fått den inn i hagen.
Forfattere
Arne HermansenSammendrag
Kålbladskimmel - en utfordring for norsk produksjon av korsblomstra grønnsaker
Forfattere
Arne HermansenSammendrag
Kålbladskimmel i kålrot, brokkoli, hodekål og blomkål
Forfattere
Arne HermansenSammendrag
Kålbladskimmel i ruccola, blomkål og brokkoli
Sammendrag
Phytophthora infestans is an important pathogen on potato and tomato during the winter seasons in the north of Vietnam and all the year around in Lam Dong province in the south of Vietnam. Data from earlier studies of isolates of P. infestans collected in 2002-2003 showed that the P. infestans population on tomato and potato from Vietnam still consist of the "old" population. However preliminary studies of P. infestans samples from 2007 indicate that this situation has started to change. Data from aggressiveness tests of P. infestans isolates on tomato and potato showed that the majority of isolates collected from tomato could not infect potato. All tested isolates originating from potato infected both hosts. From 2005-2007, field experiments in tomato and potato using IPM strategies for controlling late blight have been carried out in Lam Dong province and in Hanoi area (north of Vietnam). In these experiments, cultivars with different levels of late blight resistance and different fungicide dosages have been tested. Simple forecasting methods and sanitation procedures were also included in some of the experiments. In Lam Dong, strategies including 7 days fixed spray intervals with full dose of the fungicide mancozeb did not control late blight properly in tomato, and all 4 tomato experiments were terminated early. In the potato experiments use of a more modern fungicide could control late blight using reduced dosages. In the tomato experiments in the north no natural infection of late blight occurred during the experimental period.
Sammendrag
Phytophthora infestans is an important pathogen on potato and tomato during the winter seasons in the north of Vietnam and all the year around in Lam Dong province in the south of Vietnam. Data from earlier studies of isolates of P. infestans collected in 2002-2003 showed that the P. infestans population on tomato and potato from Vietnam still consist of the "old" population. However preliminary studies of P. infestans samples from 2007 indicate that this situation has started to change. Data from aggressiveness tests of P. infestans isolates on tomato and potato showed that the majority of isolates collected from tomato could not infect potato. All tested isolates originating from potato infected both hosts. From 2005-2007, field experiments in tomato and potato using IPM strategies for controlling late blight have been carried out in Lam Dong province and in Hanoi area (north of Vietnam). In these experiments, cultivars with different levels of late blight resistance and different fungicide dosages have been tested. Simple forecasting methods and sanitation procedures were also included in some of the experiments. In Lam Dong, strategies including 7 days fixed spray intervals with full dose of the fungicide mancozeb did not control late blight properly in tomato, and all 4 tomato experiments were terminated early. In the potato experiments use of a more modern fungicide could control late blight using reduced dosages. In the tomato experiments in the north no natural infection of late blight occurred during the experimental period.
Forfattere
Ari Lehtinen Asko Hannukkala Björn Andersson Arne Hermansen Vinh Hong Le Ragnhild Nærstad May Bente Brurberg Bent J Nielsen Jens G Hansen Jonathan YuenSammendrag
A total of 743 single-lesion isolates of Phytophthora infestans were collected in summer 2003 from Denmark, Finland, Norway and Sweden. Most of the isolates were tested for mating type, snd subsets for sensitivity to fungicides and virulence (host specific pathogenicity). Approximately 60 % of the isolates were A1 mating type in each country. Both mating types were present in 40 % of the fields where more than one isolate was tested,indicating strong potential for sexual reproduction. The proportion of metalaxyl-resistant isolates dropped under 15 % from the 60% observed in the early 1990s in Norway and Finland, possibly due to lower selection pressure because of decreased use of metalaxyl. PropamocarbHCl sensitivity remained unchanged in the Nordic countries compared to the situation in 1997-2000 in Finland. Four isolates collected from Finland and Sweden were able to sporulate in the presence of this fungicide at a concentration of 1000 mg L-1. In Norway and Finland the frequencies of virulence factors and pathotypes remained nearly unchanged since 1990s, but the mean number of virulence factors per isolate increased from 5.6 to 6.3. In Denmark and Sweden virulence factors 2 and especially 6 were more common than in Norway and Finland. In addition, in the Swedish population the frequencies of pathotypes were quite even while in other countries pathotype 1.3.4.7.10.11 was most prevalent.