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.
2006
Sammendrag
Et nærmere 2 meter høyt sperregjerde ble i april satt opp mellom første og andreårsfelt to steder i Norge (Kise og Ørlandet). Hensikten var å se om dette kunne hindre billene i det eldre feltet å komme inn i det nye. Tidligere år har vi prøvd inngjerding av mindre ruter i åkeren med svært godt resultat, men vi ville nå prøve et enklere og mer realistisk opplegg. Billene ble ikke helt stengt ute fra førsteårsfeltet med denne metoden, slik at det også ble skade der, men den var mindre enn forventet. Vi må studere billens atferd for å komme videre med gjerdemetoden (kommer f.eks billene inn i nyplantede felt allerede om høsten?), og dette vil vi gjøre i det nye prosjektet "Kontroll av snutebiller i jordbær ved hjelp av luktstoffer og andre alternative metoder".
Sammendrag
Aktiviteten til overvintrede jordbærsnutebiller (Anthonomus rubi), målt som avkuttede knopper og voksne biller, ble registrert ukentlig i sprøytede og usprøytede ruter i unge og gamle jordbærplanter. Studiet ble gjort i 9 Koronafelter i år 2000, i et distrikt med mye A. rubi på Østlandet (Nes i Hedmark). Totalt antall avbitte knopper var sterkt korrelert med totalt antall biller som ble funnet ved å riste enkeltplanter over et hvitt fat. En økning i antall voksne biller ble som regel etterfulgt av en økning i skadede knopper 1-2 uker senere. Dette viser at overvåking ved hjelp av fatmetoden har potensiale for å forutsi skade. I fem av seks felter der avlingen ble registrert ble det funnet en negativ sammenheng mellom avkuttede knopper og salgbar avling. Effekten av skadedyrsprøyting (flere sprøytinger i de fleste feltene) var relativt liten: Antall avbitte knopper gikk bare ned med 21% i forhold til usprøytede ruter, mens salgbar avling økte med 16%. Sprøytingen hindret altså en relativt liten del av den omfattende A. rubi skaden i jordbærfeltene som her ble studert, og det er siden funnet resistens mot skadedyrmidler i billlene.
Forfattere
Bernhard Speiser L Tamm T Amsler J Lambion C Bertrand Arne Hermansen Theo Ruissen Palle Haaland J Zarb J Santos P Shotton S Wilcockson P Juntharathep R Ghorbani C LeifertSammendrag
Late blight of potatoes, caused by Phytopthora infestans, is particularly difficult to prevent or control in organic agriculture. In this study, the host resistance of selected varieties to foliar and tuber blight and their yield under organic growing conditions were assessed in trials carried out in four countries (Switzerland, France, England and Norway) in 2001 and 2002. The objective was to identify new, more resistant varieties, which might replace some of the more susceptible varieties which are currently grown in organic agriculture. In each country, five test varieties were compared with two reference varieties, identical for all sites, and two local popular varieties. In addtion, the effect of copper fungicides was assessed for all varieties in England. Several new potato varieties (Appell, Derby, Innovator and Naturelle in Switzerland; Derby, Eden, Escort and Naturella in France; Sarpo Axona, Eve Balfour, Lady Balfour, Sarpo Mira and Sarpo Tomina in England; N89-1756 and N92-1538 in Norway) proved far less susceptible to foliar and tuber blight than most of the varieties currently grown. However, market requirements could restrict their introduction into practice. The copper fungicide treatment reduced foliar blight severity in all varieties tested in England and in both years, by 27 % on average, and increased yield by 20 % on average, but did not affect tuber blight. In organic farming, a shift towards the use of blight resistant varieties should be strongly encouraged, although this is unlikely to eliminate the need to use copper fungicides.
Sammendrag
Potetene vil også i 2006 krever riktig tørråtebekjempelse for å unngå redusert avling og kvalitet. I likhet med de siste årene kommer vi med en omtale av varsling og middelvalg i forbindelse med bekjempelsen av denne viktige skadegjøreren. Artikkelen er en oppdatering av tilsvarende artikkel fra i fjor.
Forfattere
Ricardo Holgado Janet Rowe Stig Andersson Christer MagnussonSammendrag
Cereal cyst nematodes, Heterodera spp., are recognised throughout the world as economically important parasites of cereals. The virulence status on cereal cultivars differs between and within different species of the H. avenae-complex, and several pathotypes occur among them. A survey during 1995-2005 in Norway revealed that Heterodera spp. is common throughout the country. Studies in Norway have recorded H. filipjevi and also additional and possibly new species. A number of cereal cyst nematode populations from various regions of Norway, Sweden and the British Isles have been analysed using molecular, morphological and host range studies during the last three years. Fifteen populations, of the initial group of forty, are being studied more closely. Studies using isoelectric focusing and silver staining have detected divergent populations of H. avenae. The Swedish populations Ringsåsen seemed to be identical to a population found in Australia and the Swedish population Halland shows a protein profile separate from H. avenae. DNA studies are being used to determine if these populations are new species. An assortment of cereal cultivars, based on an international collection used for resistance testing, differentiates three groups, H. avenae (pathotypes Ha 11 and Ha 12), H. filipjevi (pathotype "West"), and a population from central Norway close to H. pratensis. Knowledge of the diversity of cereal cyst nematodes and their multiplication rates on their cereal hosts is of fundamental importance for efficient control strategies involving resistant cultivars. In Norway, management based on these parameters are in operation and have increased yields and profits to cereal farmers.
Sammendrag
The aim of this three-year study (2001"2003) was to optimize fungicide application against anthracnose (Colletotrichum acutatum) in sweet and sour cherry orchards. The experimental sprays were applied to trees receiving normal fungicide programmes (grower schedule), although without the use of dithianon, except for the first year where only the experimental applications were applied to the sour cherry trees. Fungicide treatments were applied with either dithianon or copperoxychloride added prior to flowering or with dithianon added after flowering. Spraying with dithianon or copperoxychloride prior to flowering did not significantly reduce anthracnose compared to untreated. Two applications with dithianon during the green fruit stage (from petal fall and during the following 3"4 weeks) greatly reduced anthracnose at harvest. Three applications on green fruit did not reduce disease more than two applications. In sweet cherries, two sprays with dithianon at the green fruit stage in addition to the grower schedule reduced anthracnose at harvest from 14% to 3% in 2002 and from 15% to 1% the following year. In 2001, when very few fruit developed anthracnose, no treatment effects were evident. Treatments on green sour cherry fruit similar to those on sweet cherries reduced the attack of anthracnose from 85% to 42% in 2002 and from 51% to 12% the following year. In 2001, no treatment included only sprays on green fruit. However, one treatment, which included copperoxychloride at bud burst, one application of dithianon during flowering and two applications on green fruits, reduced anthracnose from 27% to 9%. Based on these results, cherry growers are recommended to spray twice with dithianon on green fruit if they have a history of anthracnose in their orchards.
Forfattere
Sverre Kobro Geir Kjølberg KnudsenSammendrag
Det hender at det er mark i eplene. Markene er larver av en liten sommerfugl. Den heter rognebærmøll fordi den normalt utvikler seg i bærene på rogn. I enkelte år er det for lite bær på rogna, bare da kan møllet angripe eple.
Sammendrag
Methods for measuring prevalence of Neozygites floridana in a Tetranychus urticae population collected from strawberries were developed and compared. T. urticae were extracted from leaves using a soapy water solution (0.5 ml washing detergent : 8 l water) and then placed into 80% alcohol for use in methods 1 and 2. Method 1: N. floridana-sporulating T. urticae cadavers were observed and quantified under a compound microscope (40-80X). Method 2: Adult females were mounted in lactophenol cotton blue and observed for the presence or absence of N. floridana hyphal bodies under a microscope (200-400X). Method 3: Live T. urticae females were incubated at 25ºC and 75% RH and observed for mortality and N. floridana infection under a compound microscope (6.4-40X). Method 1 was the most time-efficient method and it also allows processing of samples as time permits. Method 2 quantified significantly higher fungal prevalence than method 1 and 3, but method 2 is not considered to be reliable because hyphal bodies are difficult to detect. No significant differences were found between methods 1 and 3.
Forfattere
Shala Werner Michael Albers Terry Cryderman Danko Dimenic Robert Heyd Boris Hrasovic Sverre Kobro Stig Larsson Roger Mech Pekka Niemela Matti Rousi Kenneth Raffa Kyoko Scanlon Shane WeberSammendrag
The introduced basswood thrips, Thrips calcaratus, undergoes outbreaks on and damages American basswood, Tilia americana, in North America, but is less common on and does not cause significant damage to little-leaf linden, Tilia cordata, in its native European range. A possible explanation is that altered host relationships in North America allow increased exploitation of T. americana. Three experiments were conducted to compare host associations of T. calcaratus between T. americana and T. cordata. In a laboratory choice bioassay, T. calcaratus occupied foliage of both tree species with equal frequency. A field assay conducted in North America revealed an identical trend on planted T. americana and T. cordata seedlings planted in a paired design. In a separate field experiment bud break phenology, peak T. calcaratus emergence, and foliar development showed similar temporal patterns in 10 T. cordata and T. americana sites distributed across the insect"s native range of Europe and introduced range of North America. These results suggest that physiological and phenological differences between native and newly acquired Tilia hosts are not likely responsible for the increased impact of T. calcaratus in its introduced range. Rather, temporal escape from natural enemies seems to be the more likely explanation. This is evidenced by the stronger synchrony of the North American predator, Leptothrips mali, with the native basswood thrips, Neohydatothrips tiliae, than with T. calcaratus. Understanding the basis for increased success of T. calcaratus in its introduced range may provide insight into managing this insect in basswood forests in the Great Lakes region.
Forfattere
Sverre Kobro Trond RafossSammendrag
The presence of multiple phenological forms has previously made adults of Hoplothrips species difficult to identify. We present a set of diagnostic metric characters by which the 8 species recorded from Norway can be recognised.Some biological interpretations are also given.