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
Forfattere
Arne Hermansen Maria Herrero Elisa Gauslå Jafar Razzaghian Ragnhild Nærstad Sonja KlemsdalSammendrag
Carrot roots with cavity spot lesions from 8 different counties in Norway were sampled and Pythium species were isolated on selective medium. Pythium spp. were characterised morphologically and by species-specific PCR. Laboratory experiments with inoculations of carrot roots were performed. A total of 130 isolates out of 230 Pythium-like isolates tested with PCR were identified as pathogenic species of Pythium. These were P. intermedium (29 %), P. sulcatum (23 %), P. sylvaticum (16 %), P. violae (15 %) and a possible new Pythium species designated P. "vipa" (18 %). There were some difference between geographical regions and ages of cavities regarding the frequency of the different species isolated. When rating sunken lesions in the laboratory inoculation experiments, P. "vipa" was the most aggressive and P. violae the least aggressive species. P. intermedium and P. "vipa" caused more discolouration of the infected carrot tissue than the other species. The importance of the different Pythium spp. as agents of cavity spot in Norway is discussed.
Sammendrag
Perpetual-flowering strawberry cultivars are commonly classified as photoperiodically day-neutral, even though early investigations demonstrated long-day (LD) regulation. An important reason for this inconsistency is that these freely flowering plants are difficult to establish in a true vegetative state, and experiments have therefore, often been started using runner plants with pre-formed inflorescences. In order to circumvent this problem, we have used the perpetual-flowering F1-hybrid `Elan" that is propagated by seed, and is thus not pre-conditioned by its earlier life history. The results demonstrated a marked quantitative LD response across a range of temperatures from 9º - 27ºC. Seedlings were responsive to the LD stimulus at an early stage, and early flowering required LD exposure almost from germination. The critical daylength for the early flowering response was about 15 h at 18ºC. Because of this threshold LD response, it is concluded that regulation of flowering is truly photoperiodic in nature, and not merely an effect of additional light. Flower development was also slightly advanced by LD conditions. Stolon formation was strongly enhanced by short day conditions in combination with high temperature. Thus, not only flowering, but also runnering, was oppositely affected by photoperiod in `Elan" compared with mono-flowering cultivars. The results are discussed in relation to the photoperiodic classification of strawberries.
Forfattere
Kim Johansen Marianne TomtumSammendrag
I overvåkingsprogrammet for rester av plantevernmidler i vegetabilske næringsmidler er det tatt ut og analysert totalt 489 prøver i tredje tertial 2006. Det er analysert 359 rutineprøver av frisk frukt/bær, grønnsaker, krydderurter og poteter, seks prøver av barnemat, 43 prøver av matkorn, 68 prøver for kartlegging av vegetabilske matvarer fra Asia og 13 prøver av appelsinjuice (EU koordinert program). Det er i perioden vært to tilfeller av funn i økologiske produkter, henholdsvis sitron fra Spania og paprika fra Nederland. Det ble også gjort funn som indikerte ulovlig bruk av plantervernmidler i norsk produksjon av epler og gulrot. Resultatene fra overvåkingsprogrammet viser at 67,1 % av de undersøkte stikkprøvene av vanlig frisk frukt, bær, grønnsaker og poteter er uten påvisbare rester av plantevernmidler. I 16 varepartier er det påvist rester over gjeldende grenseverdi, hvorav ett vareparti av norske epler ble vurdert å kunne representere helserisiko. For matkorn er 67,4 % uten påvisbare plantevernmiddelrester. Ingen kornparti har rester over gjeldende grenseverdi. I kartleggings¬prosjektet "Vegetabilske produkter fra Asia" er kun ¼-del av de 68 prøvene uten rester av plantevernmidler, mens nær halvparten av prøvene inneholder rester over gjeldende grenseverdi. I ett parti chilipepper fra Thailand ble det påvist hele seks plantevernmidler som alle overskred gjeldende grenseverdi. To av varepartiene, aberginer og bønner med belg, begge fra Thailand, ble vurdert til å kunne representere helserisiko. På grunnlag av oppfølgingsprøver fra overskridelser (rettet kontroll) ble det nedlagt omsetningsforbud for fem varepartier (ett av augberginer, ett av stangselleri og tre av bønner).
Forfattere
Jan NetlandSammendrag
Berre bruke herbicid når og der det er nødvendig. Vidareutvikle økonomiske skadetersklar og operasjonalisere dei. Rotasjon med herbicid med ulike verknadsmekanismar. Ikkje meir enn to år etter kvarandre med same verknadsmekanismer uten at andre effektive tiltak kjem i tillegg. Bruk herbicid med ulike verknadsmekanismer i tankblanding eller etter kvarandre ei tid. NB! begge herbicidene må ha god verknad mot det (dei) aktuelle ugraset(a). Meir kostbar bekjempelse. Kombiner der er mogeleg med mekaniske tiltak. Ugrasharving aleine eller harving kombinert med herbicid. Vekstrotasjon som gir høve til å bruke herbicid med ulik virkemekanisme eller ikkje kjemisk tiltak. Korn-potet: svært gunstig (Sencor, Fenix, mekanis) korn-gras: svært gunstig (fenoksysyrene, populasjonsnedgang i grasåra) korn-grønsaker: begrensa (få middel å veksla mellom) korn-ertervekster: svært gunstig (Fenix, Basagran) korn-oljevekster: begrensa Inkluder der det er mogeleg ut fra erosjonshensyn, pløying og høstharving i ugrasstrategien. Kva med redusert jordarbeiding? Godt ugrasreinhold om hausten og våren Sjekk arealene regelmessig for å oppdage resistens så fort som råd og sett inn tiltak for å hinder spredning Organisert opplegg for kartlegging og påvisning av resistens??? Reingjer jordabeidingsredskaper og høstemaskiner før de blir flytta fra eit areal med resistent ugras
Forfattere
Bent J Nielsen Jens G Hansen Hans Pinnschmidt Ragnhild Nærstad Arne Hermansen Vinh Hong Le Asko HannukkalaSammendrag
Influence of weather conditions on sporangia production, release, viability and infection of potato late blight (Phytophthora infestans) was investigated in Denmark, Norway and Finland using Burkard spore traps and exposure of trap plants in field plots. High amounts of sporangia were trapped after night with long periods with high relative humidity. Sporangia produced in one humidity period were mainly released at the first humidity drop in the morning hours, but there were also some "delayed sporangia release". Local new infections occurred mainly during the morning hours when the leaves were still wet. On many days sporangia did not survive until the afternoon and the results indicate that conditions for survival of sporangia and infection are major bottlenecks for the spread and development of the disease
Forfattere
Ketil Haarstad Gro Hege LudvigsenSammendrag
Pesticides in Norwegian ground water have been monitored since 1995. Here we report data including 2004. The monitoring has focused on shallow groundwater near agricultural fields (4 locations), farm wells (22 locations) and on public water works (38 locations), 450 samples were analyzed for a total of 62 pesticide compounds and metabolites, and the result was 514 detections of single compounds. Altogether 27 pesticides and metabolites were detected; 2 insecticides, 9 fungicides and 16 herbicides. Herbicides were most frequently detected (in 79% of the samples), followed by fungicides (20%) and insecticides (1%). Pesticide concentration was generally low, although high concentrations also occurred, for example 33 "g/l of metribuzine in shallow ground water near agricultural fields, and 20 "g/l of bentazon in a farm well. Some water soluble pesticides occurred both frequently and with relatively high concentrations in shallow ground water near agricultural fields. The results show that local ground water near farms is vulnerable for contamination of pesticides and needs further monitoring. Efforts should be made to minimize contamination of wells in farming areas through education on pesticide use, monitoring and well positioning. Few pesticides were detected in ground water from water works and the concentrations were low. Monitoring of water works ended in 2002. The data show that there is a continuous need to monitor pesticides as well as selected metabolites in shallow ground water and wells near agricultural fields in Norway.
Forfattere
Solveig HaukelandSammendrag
The large arionid slug Arion lusitanicus is a serious pest in parts of northern Europe including many parts of Norway. In Norway it has mainly been a pest in home gardens but in recent years it has also spread to horticultural and vegetable crops such as strawberry and lettuce. The use of the nematode Phasmarhabditis hermaphrodita against A. lusitanicus is being investigated in an on-going research project that was initiated in 2005. A survey was conducted in 2004 to examine if the nematode P. hermaphrodita could be found occurring naturally in Norway. The result of the survey was positive which led to registration of the product Nemaslug in 2005. Several experiments have been carried out since 2005, to study the effect of both the commercial product Nemaslug and Norwegian isolated P. hermaphrodita on A. lusitanicus slugs. Laboratory and controlled pot experiments confirm that young stages of the slugs are susceptible to the slug parasitic nematode. Further work on the infection process of nematodes in slugs as well as the practical aspects of nematode use in gardens and the field will be addressed as a next step in these studies.
Forfattere
Erik JonerSammendrag
The rapid increase in development and production of manufactured nanoparticles (NP) has given rise to concern for health and environment. While toxicity in higher organisms and workers exposure have received attention and benefited from substantial research efforts in later years, the environmental impact of spreading NP and ecotoxicity have received far less attention. To the extent that NP may be toxic to higher organisms and man, the redistribution of NP from major environmental recipients like soils and sediments represents a route for exposure that may also have implication for public health. Research on environmental aspects of spreading NP has suffered from a lack of appropriate tools that allow studies on fate, mobility and uptake in organisms, particularly in dirty matrices like soil, sediments and waste. We are currently exploring the possibilities for tracing different NP (metals, oxides, CNT) in soil and sediments/water using functionalization, radiotracers, and fluorescence labelling, and exploit these tools in quantification of adsorption, mobility and transfer, including organismal uptake and internal distribution/accumulation in different organs of earthworms and fish. In combination with an increasing knowledge on toxicity, these tools, if proven suitable, may permit a range of studies on environmental behaviour of NP which can form a basis for environmental risk assessment, and ultimately regulatory actions that may limit exposure of biota and Man.
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
Good soil structure is recognised to be of key importance in organic farming, and soil compaction poses a major threat with respect to this. The relative importance of tractor weight (2-4 vs. 5-7 Mg), ploughing depth (ca. 15 vs. 25 cm) and wheel placement during ploughing (in-furrow vs. on-land) have been studied for four years on two soil types (well-drained loam and imperfectly drained silty clay loam) in southern and central Norway. On the site with imperfectly drained silty clay loam supposed to be most suceptible to soil compaction, the soil aeration and penetration resistance, but not the yield of barley, was affected by the treatments imposed. On the site with the well-drained loam, shallow ploughing with the heavier tractor and wheel in-furrow caused lower yields of wheat, but not of barley than did the other treatment combinations. This may partly be related to reduced air permeability and volume of air filled pores at 18-22 cm and partly to a higher incidence of perennial weeds after shallow than after deep ploughing.