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
Venche TalgøSammendrag
In April 2007, orange-red pustules were found in needle scars on defoliated, dead shoots on a nordmann fir (Abies nordmanniana) Christmas tree in Rogaland County in south western Norway. A microscope slide made from the pustules revealed Fusarium-macrospores.
Sammendrag
In April 2007, orange-red pustules were found in needle scars on defoliated, dead shoots on a nordmann fir (Abies nordmanniana) Christmas tree in Rogaland County in south western Norway. A microscope slide made from the pustules revealed Fusarium-macrospores. On average they were 40.2 µm long and 2.9 µm wide (n=50). No microspores were found. A red coloured culture was obtained by transferring spore mass from a sporodochium to PDA (potato dextrose agar) with a sterile needle. The culture was transferred to SNA (spezieller nährstoffarmer agar) where macrospores developed. The majority of the spores had three septa, most of them were slightly curved, apically bent, basal cells were foot shaped, and spores were long and slender. Six singlespore cultures appeared identical on SNA. Two were chosen for an inoculation test. This test took place on 4 June 2007 in a polyethylene tunnel where the plants were kept during the whole experimental period. Nearly fully grown current year shoots on container grown nordmann fir transplants were inoculated by placing PDA agar plugs with fungal growth at the base of some unwounded needles on each shoot. Twelve transplants were used for each of the two isolates. The plants were covered with polyethylene bags for five days. After the bags were removed, the foliage was kept wet throughout the growing season by 1-3 minutes (depending on temperature) overhead irrigation every third hour. Brown shoots developed during the summer regardless of which singlespore isolate that had been used for inoculation. Samples from brown shoots were collected 20 October. No sporodochia, like we found under field conditions in April, had developed on the inoculated shoots. Neither did they develop after incubation in the laboratory. Only a whitish, fluffy mycelium was seen. CZID (Czapek dox iprodione dichloran agar) was used for reisolation from the dead shoots. From each group of 12 inoculated plants, two and three Fusarium-cultures were obtained, respectively. No symptoms were observed and no Fusarium sp. was isolated from the control plants (exposed to same treatment, but agar plugs with no fungal growth had been used). The Fusarium strain could not be accurately identified to species when the FUSARIUM-ID database v. 1.0 (http://fusarium.cbio.psu.edu) was searched with partial sequence of TEF (translation elongation factor 1-"). The original culture plus the two single spore cultures used for inoculation had identical TEF sequences which were most similar to F. acuminatum (97% identity). One out of six single spore cultures from each of the five reisolates, was sequenced. One of them matched the original culture, but the other four were most similar to F. avenaceum (98% identity). Different from the original culture, the F. av.-like isolates had both macro- and microconidia (0-3 septa, oval spore shape). On PDA, the F. ac.-like culture grew 25 mm in 72 hours (dark and 25°C) and the four F. av.-like cultures grew between 32 to 40 mm. They could not be distinguished by colour. Hyphal coils were found on both species, but were most prominent on the F. ac.-like culture. The fact that sequencing revealed involvement of two Fusarium-species, makes is difficult to draw conclusions about pathogenicity, but since the control plants showed no symptoms, there may be indications that the F. ac.-like fungus killed the inoculated shoots and that the F. av.-like fungus came in as a secondary invader from the environment inside or outside the tunnel. F. acuminatum is reported as a pathogen on conifer seeds and seedlings, but to our knowledge this is the first report of a F. ac.-like fungus causing dieback on a Christmas tree.
Forfattere
Venche TalgøSammendrag
Det er ikke registrert sammendrag
Forfattere
Venche TalgøSammendrag
Soppane Delphinella abietis and Herpotrichia parasitica gjer begge stor skade i nokre edelgranfelt på Vestlandet. Delphinella er mest utbreidd av dei to og gjer omfattande skade frå Hardanger og nordover. Begge soppane er luftborne og angrip nålene.
Forfattere
Venche Talgø Thomas Cech Gary Chastagner Iben Margrete Thomsen Kathy Riley Kurt Lange Arne StensvandSammendrag
Current-season needle necrosis (CSNN) is a poorly understood disease with significant impact on the marketability of fir (Abies spp.) Christmas trees and boughs in North America and Europe. Initial symptoms appear on needles soon after bud break as tan to yellow-coloured spots, which turn reddish brown during the summer. The symptoms are observed on noble fir (A. procera), nordmann fir (A. nordmanniana) and grand fir (A. grandis) on both continents. The etiology of CSNN is unknown. In the USA, Ireland and Denmark, research has indicated that CSNN is a physiological disorder. Isolation and examination of host tissue at the onset of symptoms failed to identify a pathogen. In the USA, foliar applications of very high rates of calcium, or shading noble and grand fir shoots during shoot elongation, significantly reduced CSNN damage. Research in the USA and Denmark also showed that CSNN susceptibility in noble fir is under strong genetic control. In Germany, the fungus Kabatina abietis Butin & Pehl sp. nov. was isolated for the first time in 1992 from grand fir needles with CSNN symptoms, and later from nordmann and noble fir. K. abietis was also recently isolated from symptomatic nordmann fir needles on samples from Austria, Norway and Denmark. Given the uncertain etiology of CSNN, inoculation tests will be carried out in Norway, and fungicide trials will be performed in Austria, Denmark, Germany, Norway and the USA in 2008, in an effort to determine the potential role of K. abietis in the development of this disease.
Forfattere
Venche TalgøSammendrag
Det er ikke registrert sammendrag
Forfattere
Venche TalgøSammendrag
CSNN er forkorting for sjukdomen som på engelsk vert kalla "current season needle necrosis". Mykje tydar på at sjukdomen skuldast soppen Kabatina abietis. Smitteforsøk ved Bioforsk Plantehelse gav CSNN-symptom på både frøplanter og utplantingsplanter av nordmannsedelgran.
Sammendrag
I Nordamerika og Europa har der siden 1980-erne været observeret misfarvede pletter på årsskuddenes nåle på nordmannsgran (Abies nordmanniana), nobilis (A. procera) og grandis (A. grandis). Skadebilledet ser ud til at være identisk, men optræder især på grandis og nobilis i USA og på nordmannsgran og nobilis i Europa. I USA har skaden været opfattet som fysiologisk og udløst af bestemte vejrforhold (Chastagner 1997). De første symptomer er lyse pletter på nålene kort efter udspring (figur 1). I løbet af sommeren bliver pletterne rødbrune (figur 2), og hele nålen kan blive nekrotisk og falde af (figur 3). Fænomenet har gået under navnet "røde nåle" i Danmark (Christensen 1981, Thomsen et al. 1997, Nielsen & Christensen 1997a, b) og "current season needle necrosis" (CSNN) i USA og Irland (Chastagner et al. 1990, Sinead 2000). Det var først efter 2000, at CSNN og "røde nåle" på nordmannsgran blev anset for at være identiske fænomener (Thomsen 2002). I Tyskland og Østrig har lignende skadesbilleder været koblet sammen med tilstedeværelsen af en svamp, som hedder Kabatina abietis (Butin & Pehl 1993, Perny et al. 2002, Lange 2007). Det tyske navn er Kabatina-Nadelbräune, dvs. brunfarvning af nåle. Illustrationerne i disse publikationer tyder på, at de omtalte symptomer er de samme, som vi kalder CSNN i det internationale juletræsmiljø. Dog understreger Kurt Lange, at man skal isolere svampen for at være helt sikker på diagnosen, samt at der ofte forekommer lignende symptomer uden svamp, således hyppigt i 2007 (pers. medd. i samtale under Langesømessen 2007). Blandt danske dyrkere har der også været en opfattelse af, at røde nåle kunne skyldes et svampeangreb. Dette er indtil nu blevet afvist af danske og nordamerikanske forstpatologer, som anser de forskellige, fremkommende nålesvampe for sekundære. Men mistanken er alligevel ikke helt ubegrundet, og det synes at være på tide at få sagen afklaret. Dette skal ske i et fælles dansk-norsk PAF projekt i samarbejde med andre lande.
Sammendrag
Small plants of nordmann fir (Abies nordmanniana) were grown in chelator-buffered nutrient solution for 31 days. The treatments were arranged in a factorial design with normal and low supply of either Ca or Mg. Fixed free metal activities calculated with Geochem-PC 2.0 (Parker et al. 1995), were obtained in the nutrient solution by addition of HEDTA [N-(2-hydroxyethyl)-ethylenediamine-triacetic acid]. At the end of the experiment, mineral analyses of several elements were obtained from new shoots, roots, old needles and stem. The nutritonal constraints of Ca and Mg significantly affected the mineral composition of the different plant parts. Results will be further reported in the full abstract. The methodology of chelator-buffered nutrient solutions seems appropriate for the study of mineral nutrition to nordmann fir.
Sammendrag
Extensive damage by the needle parasites Delphinella abietis and Herpotrichia parasitica (Herpotrichia Needle Browning) was recently observed at the west coast of Norway. D. abietis was by far the most widespread, but once established in the field, the damage potential seemed to be equally high for both pathogens. D. abietis occurred on subalpine fir (Abies lasiocarpa), Turkish fir (A. bornmuelleriana), Siberian fir (A. sibirica), and nordmann fir (A. nordmanniana) in Christmas tree plantations, and minor damage was seen on Noble fir (A. procera) for bough production. H. parasitica was found on Turkish fir and nordmann fir in Christmas tree plantations. None of the diseases are new to Abies spp. in Norway, but they have not previously been reported from Christmas tree fields.