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.
2007
Sammendrag
The prediction of infection periods for lettuce downy mildew (Bremia lactucae) is based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, we monitored release of B. lactucae spores in relation to the climatic conditions in lettuce fields to evaluate the performance of existing forecasting models in timing of fungicide applications for management of lettuce downy mildew in Norway. In 2005, epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Sporulation events were compared to predicted spore production events in Modell-Analys (MA). At the two locations, 76 % and 74 % of the spores were trapped between 08.00 and 16.00, respectively. Spore concentration icreased with decreasing relative humidity (RH), ofting coinciding with increasing solar radiation and temperature. Spore production events predicted by MA were correct at 66 % of the days. However, when the criteria for spore production were adjusted, 78 % of the days were correctly predicted.
Sammendrag
Several models for prediction of infection periods for lettuce downy mildew (Bremia lactucae) are based on the assumption that spores are produced at night and released in the early morning. The divergent light conditions at Nordic latitudes might affect both sporulation and spore release. Therefore, during the period 2001 to 2005 a total of 13 field trials were established in late season lettuce fields to evaluate efficacy of fungicide applications made according to the models PlantPlus (PP) and Modell-Analys (MA) in Norway. Disease severity varied from 0 to 89.4 % in unsprayed control plots at harvest. Fungicide treatments had a significant effect compared to untreated control in all but two of the field trials with disease incidence over 1 % at harvest. Fungicide applications at 10-day intervals and according to PP and MA resulted in an average of 3, 2.5 and 3.3 applications, respectively. There were no significant differences in disease severity at harvest between treatments according to 10-day interval, PP and MA for any of the field trials. Epidemics were created at two field locations that had no previous lettuce production, and a total of 59 days of spore trapping permitted the study of spore release under natural conditions. Spore production events predicted by MA were correct at 66 % of the days. However, when adjusting the criteria for spore production, 78 % of the days were correctly predicted.
Sammendrag
Forsøk med varsling av salatbladskimmel i perioden 2001-2005 ble presentert
Sammendrag
We evaluated direct and interactive effects of light quality and intensity, temperature and light, diurnal rhythms, and timing of high relative humidity during long day lengths on sporulation of Bremia lactucae, the causal agent of lettuce downy mildew, using inoculated lettuce seedlings and detached cotyledons. Suppression of sporulation by light was strongly dependent upon temperature and there was little suppression at "10°C. The most suppressive waveband was in the range from 400 to 450 nm, although a lesser effect of wavebands from 450 to 500 and 500 to 550 nm could be detected. At 15°C, near the lower threshold for suppression of sporulation by light, a clear diurnal pattern of sporulation was observed independent of light and darkness. This diurnal rhythm potentially could interact with light and temperature to confound the results of controlled environment studies, and may be the controlling factor in timing of sporulation at low temperatures. Forecasting models that currently use sunrise and sunset to delimit periods conducive to sporulation can be adapted to short nights and extended twilight conditions by incorporating the effects reported herein. Additionally, models of sporulation could be adapted to better reflect a decrease or absence of the suppressive effect of light at
Sammendrag
Varsling av bladskimmel i grønnsaker ble beskrevet
Sammendrag
Virulence characteristics of Bremia lactucae populations from lettuce crops in the southeast and southwest of Norway from 2001 to 2005 were studied in relation to virulence factors (v-factors) and virulence phenotypes (v-phenotypes). The frequencies of 19 v-factors were analysed, and phenotypic diversity was calculated in relation to v-factors and v-phenotypes. A total of 39 different v-phenotypes were identified from the 58 samples analysed. Four of these were identical with the previously denominated races Bl:17, 18, 22 and 24. The most commonly occurring v-factors were v1, v2, v4, v5/8, v6, v7, v10, v11, v12, v13 and v18. V-factor v17 was not present in any of the tested isolates and v36 was found only once. V-factor v38 was first seen in 2004, coinciding with the observations of broken resistance in many cultivars. The population of B. lactucae in Norway was diverse, but not considerably different from other European populations of this pathogen.
Sammendrag
Virulens for salatbladskimmel i Norge ble presentert
Sammendrag
Foredraget presenterer resultater fra forsøk der virkningen av kontinuerlig belysning på fekunditet, utvikling og overlevelse hos veksthusmellus (Trialeurodes vaporariorum) ble undersøkt.
Sammendrag
Results from trials with the use of Macrolophus caliginosus on tabacco bankerplants to control whiteflies (Trialeurodes vaporariorum) in cut roses in a commercial greenhouses were presented.
Sammendrag
Økologisk landbruk er eit satsingsområde for norske styresmakter, offentleg forvalting og for fleire næringsaktørar. Etterspurnaden etter og omsetting av økologiske varer har auka sterkt dei siste åra. Tilhøva ligg til rette for auka produksjon av økologisk frukt og bær, likevel er produksjonen liten.