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.
2002
Sammendrag
Artikkelen gir en oversikt over hvilke soppmidler som bør velges, og når en bør sprøyte mot tørråte.
Populærvitenskapelig – Strategier for bekjempelse av salatbladskimmel
Arne Hermansen, Berit Nordskog
Sammendrag
Forebyggende tiltak og kjemisk bekjempelse av salatbladskimmel er nærmere omtalt.
Sammendrag
Leaves infected by Phytophthora infestans were collected from potato fields in southern Norway in the growing season of 2000 and 2001. Oospores were found in 8 out of 9 fields, in different cultivars and in unsprayed and sprayed fields. Oospores containing leafdiscs were buried in soil under field conditions in 1998 and tested for viability. There was no decline in viability between burial for 20 and 31 months.
Sammendrag
Phytopththora infestans is an important pathogen on potato and tomato in Vietnam during the winter season. There are no earlier reports on studies of P. infestans populations in this country. During January 2002 leaf samples were collected from potato and tomato in three provinces in north of Vietnam; Lao Cai, Hanoi and Hai Phong. About 120 pure isolates were obtained. Results from testing of these isolates for mating type, metalaxyl resistance and mitochondrial DNA haplotype will be presented.
Sammendrag
Five compost samples from organic household waste were analysed for suppression of damping-off caused by Pythium ultimum and Rhizoctonia solani on cucumber. Four of the samples were in some degree suppressive to P.ultimum. No one of the samples were suppressive to R. solani.
Sammendrag
Både insektpatogene sopper og parasitoider er viktige for reguleringen av skadedyr i økologisk og integrert fruktproduksjon. To studier ble gjennomført for å klargjøre biologien til dette komplekset av naturlige fiender og for å undersøke mulighetene for å bruke insektpatogen sopp i biologisk kontroll av kirsebærbladlusa (Myzus cerasi). Foreløpige resultater presenteres i denne artikkelen. I den første undersøkelsen ble forekomsten og viktigheten av insektpatogene sopper og parasitoider som naturlige fiender til M. cerasi undersøk gjennom to påfølgende sesonger. Foreløpige resultater viser at tidlig i sesongen er det først og fremst parasitoider som blir funnet i døde bladlus. Noen få individer infisert med sopp fra klasse Hyphomycetes (Verticillium lecanii) ble også funnet i denne delen av sesongen. Fra midten av juli ble sopp fra orden Entomophthorales (Entomphthora planchoniana, Erynia neoaphidis and Conidiobolus obscurus) funnet i døde bladlus. Antall bladlus drept av sopp ser ut til å øke mot slutten av juli. I studie nummer to ble effekten av soppmidler or dekking mot regn på insektpatogene sopp og tettheten av M. cerasi undersøkt. Foreløpige resultater fra dette studiet indikerer at søtkirsebærtrær som ikke dekkes og som ikke behandles med soppmidler muligens gir et brattere fall i M. cerasi tettheten mot slutten av sesongen. Effekten av soppmidler og dekking mot regn på M. cerasi drept av insektpatogene sopper har ikke blitt evaluert enda.
Sammendrag
Determining the level of pathogenic fungi and other microorganisms during colonization of the host is central in phytopathological studies. A direct way is to monitor fungal hyphae by microscopic examination, but indirect chitin and ergosterol-based assays have been among the most applied methods in determining fungal biomass within host tissues. Recently real-time technology is increasingly receiving attention as a way to follow infection agents in host tissues.We study the molecular basis of host defense responses, using the coniferous host Norway spruce (Picea abies) infected with the basidomycete Heterobasidion annosum as the experimental system. This basidiomycete is the major root rot causing pathogens in conifers of all age classes.In order to screen host material for differential resistance towards H.annosum for both scientific and commercial reasons, it is a necessity to reliably quantify the fungal colonization of the host tissues. Therefore, the aim of this study was to develop and compare the sensitivity of a real-time PCR assay to an ergosterol based method for determining the rate of colonization by H.annosum in inoculated spruce material. We also applied the methods to rank the infection level of the pathogen on the spruce tissue culture clones.We were able to develop a quantitative multiplex real-time PCR procedure that reliably detecting down to 1pg H.annosum DNA and 1ng host DNA in DNA extracted from infected tissues. There was a very high correlation between the fungal-biomass/total-biomass and fungal DNA-total DNA rankings obtained with ergosterol and real-time PCR respectively, strengthening the credibility of both methods.Based on both ergosterol and real-time PCR, it was clear that some spruce clones were faster and more heavily infected than others. These results indicate that both ergosterol and this real-time procedure can be useful methods to screen different spruce material for their relative resistance to the pathogen H.annosum.
2001
Sammendrag
Seasonal production of spores (conidia) of Monilinia laxa (Aderh. & Ruhl) Honey on overwintering mummified fruits, blighted flowers and fruit spurs, and newly infected flowers of sweet cherry (Prunus avium L.) was investigated in Norway in 1997-1999. Infected plant parts were incubated in saturated air for 48 h prior to washing in distilled water, followed by a quantification of conidia from the spore suspensions with a light microscope. Mummified fruits or fruit spurs containing blighted flower and leaf parts, placed on the ground in the spring or the preceding autumn, more quickly depleted their inoculum compared to similar plant parts still hanging in trees. Conidia were produced in high numbers on mummified fruits left hanging in trees for 2-3 years after infection. In 1997, the conidial production on fruit mummies in trees was relatively even during the growing season. The year after, the highest sporulation on mummified fruits in trees occurred prior to flowering, and by harvest the sporulation was reduced by 92%. The wet weather that occurred in 1998 probably depleted the inoculum earlier than in 1997, when the summer was drier. The major production of conidia from fruit spurs occurred prior to or around bloom, and very few conidia were observed at harvest. Infected flower and leaf parts attached to the overwintering fruit spurs contained higher numbers of conidia than the fruit spurs themselves. Flowers infected in the spring produced most conidia during the first two months after infection, however, if remaining attached to the fruit spurs, they produced conidia during the entire season. Infected overwintered flowers produced 3-10% as many conidia as newly infected flowers in May and early June. The maximum production of conidia from single overwintered mummified fruits was more than 10 times the conidial production from an overwintered fruit spur or newly infected flower at their respective times of peak sporulation
Sammendrag
Four methods were evaluated in measuring resistance of strawberry cultivars to crown rot caused by Phytophthora cactorum. Meristem propagated plants grown in vitro were inoculated with mycelial discs. Four to five days after inoculation, it was possible to distinguish between cultivars with large differences in susceptibility to the disease. Ten days later, all plants were totally necrotic making it impossible to distinguish between cultivars. When detached leaves were inoculated by inoculating a plug of mycelium into the petiole, disease symptoms developed more slowly in resistant cultivars, but leaf age greatly affected the rate of symptom development. When plug plants (not cold stored) were lightly wounded in the rhizome with a scalpel and inoculated with either zoospores or mycelium, differences in disease development between cultivars were mainly as would be expected from previous information on susceptibility, but both age and size of plants influenced the rate of disease development. Unwounded, inoculated plants did not develop symptoms. When cold-stored plug plants were either unwounded or lightly wounded with a scalpel in the rhizome and inoculated with zoospores, the relative rates of disease development consistently reflected the susceptibility to crown rot. At the time of final assessment, disease was much more severe in wounded plants, but the relative susceptibility of cultivars was not affected by the wounding.
Sammendrag
Skildring av prosjektet: Tiltak mot bitterrote i søtkirsebær. Planlagt aktivitet.