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.
2000
Sammendrag
Phytophthora infestans was isolated from potato leaves and tubers collected from different parts of Norway in 1993-98. Isolates were assessed for mating type, DNA fingerprints, resistance to metalaxyl and virulence phenotype. Differences in the A1/A2 ratio were evident among regions and A2 was not found in northern areas. In the southern part of the country the A2 frequency was relatively stable and 26 % of the isolates (n=1144) was mating type A2. Metalaxyl resistance was found in 31-59 % of the isolates in the period 1996-98 (n=988). All known virulence genes were found among isolates tested in 1996 (n=105), and race 1.3.4.7.10.11 was most common (resistance gene R9 was not included in the differential set). Oospores were observed in potato leaves from three locations in the southern part of Norway. RG57 fingerprints were determined for 102 isolates from 1996. A large number of genotypes and high genetic distances between the genotypes were found, which indicates that sexual reproduction is contributing significantly to the genetic variation of P. infestans in Norway. Validation of the warning system TELEVIS was carried out at one location in 1996-99. Treatments according to TELEVIS resulted in fewer sprays than conventional strategy without significant differences in haulm and tuber infections.
Forfattere
Arne HermansenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Phytophthora infestans was isolated from potato leaves and tubers collected from different parts of Finland in 1990-96 and Norway in 1993-96. Isolates were assessed for mating type, resistance to metalaxyl and virulence phenotype. In Finland, 15 % of the isolates (200 isolates tested) and in Norway 25 % of the isolates (642 isolates tested) were A2 mating type. Differences in the A1/A2 ratio were evident among regions and A2 was not found in northern areas. In Finland the frequency of metalaxyl-resistant isolates (1834 isolates tested) decreased from 59 % in 1990-95 to 2 % in 1996. In Norway 59 % of the isolates (491 isolates tested) were resistant to metalaxyl in 1996. All known virulence genes were found in both countries (269 Finnish and 105 Norwegian isolates tested) and race 1.3.4.7.10.11 was most common (resistance gene R9 was not included in the differential set). Oospores were observed in potato leaves from three locations in the southern part of Norway. The implications of the `new" populations in the Nordic countries are discussed
Sammendrag
Artikkelen beskriver utseende, vertplantespekter og kjemisk bekjempelse av ferskenbladlus og gir en oversikt over hva vi vet om resistens hos ferskenbladlus i Norge pr. idag. Dyrkere inviteres til å sende inn ferskenbladlus til en kartleggingsundersøkelse av resistens hos norske populasjoner av ferskenbladlus.
Sammendrag
A rapid and sensitive method was developed to discriminate between Seiridium cardinale and Seiridium cupressi, the fungi causing severe cankers on common cypress in the Mediterranean area. The method amplified sequence variants in the ITS2 region of ribosomal DNA using the polymerase chain reaction (PCR), followed by polyacrylamide gel electrophoresis, to reveal single-strand conformation polymorphism (SSCP) between the two species. The greatest separation pattern was obtained with a gel matrix containing 7-10% formamide and 3-5% glycerol under optimized running conditions, which were found to be 30-40 V at 4-5 degrees C for 4-8 h. Sequence homology among isolates within each of the two species caused no mobility shifts, with all isolates displaying the same migration pattern. A few base differences between S. cardinale and S. cupressi caused markedly different migration patterns, allowing differentiation of the two pathogens. Differences between these fungi at the genetic level are consistent with known data on morphological, physiological and pathogenic characteristics. SSCP analysis constitutes a rapid and easy-to-perform method by which to recognize and distinguish closely related organisms, and has considerable potential for use in diagnosis and taxonomy.
Forfattere
Isabella BørjaRedaktører
Bjørn ØklandSammendrag
Det er ikke registrert sammendrag
Forfattere
Isabella BørjaRedaktører
Richard HorntvedtSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Nina TrandemSammendrag
Det er ikke registrert sammendrag
Sammendrag
Vi undersøkte fenologi og kjønnsratio (andel hunner) til 15 arter snylteveps som parasitterer havrebladminerflue i Norge. Studiet gikk over 6 sesonger i byggskiftet i et økologisk drevet felt ved Norges Landbrukshøyskole, og det ble brukt Malaisefeller som innsamlingsmetode (en i åkerkanten og en 60 m inn i byggskiftet). Resultatene tydet på at snyltevepshunnene var mer knyttet til kanten enn hannene og verten sin, og at mange av snyltevepsene vandret ut av åkeren en stund før tresking. De to vanligste snyltevepsartene var Cyrtogaster vulgaris (en puppeparasitt) og Diglyphus begini (en larveparasitt). Førstnevnte hadde en særlig nær tilknytning til kanten, og tidligere studier har vist at denne kan overvintre som voksen i f.eks grastuer i kanten. Hos sistnevnte fant vi en tetthetsavhengig kjønnsratio i fellefangstene: Jo flere individer i fellene, jo lavere andel var hunner