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.
2005
Sammendrag
Fri forgreining i julestjerne forårsakes av et fytoplasma, en bakterielignende organisme beskrevet som "Poinsettia branch inducing phytoplasma". I forskningsprogrammet: "Fundamental studies on postharvest physiology end plant health" har vi studert den relative mengden av slikt fytoplasma på ulike punkter inne i julestjerneplanter. Så langt kan vi måle variasjoner i fytoplasmamengde innen den enkelte plante, og mellom sortene "Lilo" og "Millenium", samt mellom ulike temperaturer og lysnivåer.
Sammendrag
I 2004 og 2005 ble det utført en del feltforsøk for å undersøke effekten av to kommersielle preparater av nyttenematoder, Nemasys H og Nemsays L, mot larver av veksthussnutebillen. Resultatene viser at Nemasys H har ingen eller svært dårlig virkning når gjennomsnittstemperaturen i jorda (5-10 cm dybde) faller under 12 grader. For Nemasys L var virkningen ved slik lav temperatur noe bedre, men ikke så god som forventet. Langtidsvirkningen av nematodeutslippetne er ikke undersøkt, men basert på erfaringer fra feltforsøk utført hittil anbefales det å behandle med Nemasys H om høsten eller tidlig på våren når jordtemperaturen er 12 grader eller mer.
Forfattere
John Skartveit Lita Greve Sverre KobroSammendrag
A total of 5958 specimens belonging to Bibio clavipes Meigen, 1818 (Diptera, Bibionidae) were identified from light trap catches during the years 1988 to 2004. The abundance varied between years from zero up to 3100 specimens
Forfattere
Trond Hofsvang Heidi Heggen Helge Sjursen Birgitte Henriksen Tor Munthe Jan Netland Ricardo Holgado Ole Martin EkloSammendrag
Intergert plantevern går ut på å kombinere flere ulike bekjempelsestiltak for å redusere bruken av kjemiske plantevernmidler. For å kunne utføre integrert bekjempelse, må man vite hvordan skadegjørerne ser ut, hvordan de lever og hvilke tiltak som er aktuelle. I boka finnes nærmere beskrivelse av vanlige ugras, skadedyr og sjukdommer i korn. Retningslinjer for integrert plantevern i korn finnes også i boka.
Forfattere
Heidi Heggen Brita Toppe Inger Sundheim Fløistad Arild Sletten Dag-Ragnar Blystad Ricardo Holgado Ole Martin Eklo Erlend SpikkerudSammendrag
Integrert plantevern går ut på å kombinere flere ulike bekjempelsestiltak for å redusere bruken av kjemiske plantevernmidler. For å kunne utføre integrert bekjempelse, må man vite hvordan skadegjørerne ser ut, hvordan de lever og hvilke tiltak som er aktuelle. I boka finnes nærmere beskrivelse av vanlige ugras i veksthus, skadedyr og sjukdommer på blomstrende potteplanter, dekorasjonsplanter, utplantingsplanter og snittblomster. Nytteorganismer som brukes i biologisk bekjempelse i veksthus blir også beskrevet. I boka er det tatt med retningslinjer for integrert plantevern i snittroser, julestjerne og utplantingsplanter
Sammendrag
Julestjerne dyrkes ved temperaturer ned til 15ºC, noe som kan være et problem ved bruk av nytteorganismer. Vi har utført forsøk for å undersøke effekten av forskjellige utslippsmetoder av snyltevepsen Encarsia formosa og rovtegen Macrolophus caliginosus ved vanlig klimaprogram i julestjerne. Resultater viser at snylteveps og rovteger er effektive mot bomullsmellus dersom de slippes ut tidlig og det brukes relativt høye doser. Bomullsmellusa må bekjempes i løpet av de første ukene etter innpotting, før temperaturen senkes til 18ºC, for da er ikke nytteorganismene lenger så effektive.
Sammendrag
Næringsstofmangel hos nordmannsgran kan ofte erkendes på nålefarven. Dette videnblad giver eksempler på nålesymptomer ved mangel på kvælstof, magnesium, kalium og mangan.
Forfattere
May-Guri Saethre Trond HofsvangSammendrag
Timed catches of Cydia pomonella (L.) males in sex pheromone traps were used to investigate the influence of twilight and climatic parameters on the flight activity of the moths at different latitudes. Traps were operated from 15 May until 31 July at several locations between 59ºN and 60ºN in south-eastern Norway, and at Sogndal (61ºN) in western Norway, during 1997-2000. Time and duration of twilights were calculated from May-August for each trap-location, and compared with the activity of C. pomonella. Flight response appeared to be determined by the daily photoperiod, corresponding to time of sunset at the different latitudes involved in the study. This response began about two hours before sunset, and declined around 23:00 and 24:00 hours in the evening, in western and eastern Norway, respectively. Main flight activity in both eastern and western Norway was recorded when temperatures were in the range 10-20 ºC, the relative humidity was above 50 %, and at wind speeds below three m/s at the time of capture. In Norway, light conditions are suitable for C. pomonella flight activity all night long during the entire lifetime of the adult moths. It is concluded that temperature is the limiting factor for flight at high latitudes.
Sammendrag
In a survey in one conventional and four organic apple orchards in southeast Norway insect pathogenic fungi and parasitoids as natural enemies of green apple aphid (Aphis pomi) and rosy apple aphid (Dysaphis plantaginea) were studied weekly throughout the summer 2002 and 2003. Four species of insect pathogenic fungi in the order Entomophthorales were observed to infect both aphid species. These were Entomophthora planchoniana, Neozygites fresenii, Erynia neoaphidis and Conidiobolus obscurus. The highest fungal infection level in A. pomi was 39,6 % and 33,3 % in D. plantaginea. Neozygites fresenii was the fungal species being the most prevalent. This fungus also seemed to cause an epizootic in A. pomi and to decrease the aphid population in one organic location during the summer 2002. Parasitoids were a more important mortality factor in A. pomi than in D. plantaginea, and the highest parasitization recorded in A. pomi was 30 %. Four species of primary parasitoids hatched from A. pomi: Binodoxys angelicae, Lipolexis gracilis, Praon sp. and Ephedrus sp. Hyperparasitoids that hatched from A. pomi were Dendrocerus carpenteri, Alloxysta pleuralis, Phaenoglyphis villosa and Asaphes suspensus. Only one individual of D. plantaginea was parasitized and this parasitoid was Ephedrus persicae. Both fungi and parasitoids were abundant early in the season. The fungi were found from late June and throughout the season in some locations in 2002. Resting spores of N. fresenii were found in A. pomi in July. The parasitization showed two tops, one early in season (June/July) and one late in season July/August. Fungal infections were more prevalent than parasitoids in D. plantaginea. Fungi and parasitoids were equally important in A. pomi.
Forfattere
Ricardo Holgado Stig Andersson Christer Magnusson Janet RoweSammendrag
A survey of cereals, carried out in 1995-2005 in Norway, revealed that Heterodera spp. are common throughout the country. Nematodes belonging to the H. avenae complex were recorded from the county of Agder in southern Norway (58.08o N) to the county of Nordland in the north (65.5o N), and this so far is the most northern location reported for Heterodera in cereals. Studies in Norway have recently recorded H. filipjevi and also additional and possibly new species. H. filipjevi is of economic importance in Scandinavia. It was first recorded in the beginning of the 1970s and then referred to as the "Gotland strain of H. avenae". Biotests carried out in Sweden demonstrated the occurrence of two pathotypes, "East" and "West", named according to their geographical distribution. In Norway H. filipjevi, was first recorded causing damage to winter rye, Compared to H. avenae, H. filipjevi has the ability of hatching easily and at low temperatures, this ability of rapid hatch suggests that field population densities could easily be underestimated if based on cyst extractions only. Hence, accurate assessments of pre-plant densities of H. filipjevi require quantification of infective juveniles in soil. Nematode management practices must be based on the knowledge of the population dynamics and the threshold levels needed to cause economic damage. Tests of 63 cereal cultivars on the Norwegian market revealed 13 oat and six barley cultivars to be resistant to H. filipjevi "West" It is important that resistant cultivars of barley are recommended when nematode populations are high, as resistant barley is more tolerant than resistant oats. However even in rotations with resistant barley the farmer should be prepared to accept some yield losses in the first year of management. One important challenge in the management of H. filipjevi is the common occurrence of mixed populations. H. avenae "sensu stricto" and/or its slightly diverging form "Våxtorp" is often found together with H. filipjevi. From our experience the dynamics of mixed populations needs a stronger emphasis in management systems for cereal cyst nematodes. Our knowledge of the occurrence and distribution of cereal cyst nematode species and pathotypes in Norway has increased, and the screening of cultivars for resistance against various populations particularly H. filipjevi, H. avenae "sensu stricto" and the "Våxtorp"-type has been intensified. Hence, today farmers can be provided with control strategies which are easily implemented. With this management system, farmers in the county of Vestfold have increased cereal yields. After 3-4 years of implementation farmers have reported yield increases averaging 1000 kg ha. Compared to the earlier situation (when control was not practiced), a full implementation of the current management program in the county of Vestfold has been estimated to give an annual economic gain in the order of "800 000.