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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

Sammendrag

Cleistothecia on leaves of deciduous perennials are often dispersed before leaf fall to other substrates. In contrast, strawberry leaves remain attached during winter, and cleistothecia of Podosphaera macularis remained attached to these leaves. Release of overwintered ascospores was coincident with renewed plant growth, and pathogenicity of ascospores was confirmed. Upper and lower surfaces of emergent leaves were similarly susceptible, but upper surfaces were obscured by folding in emergent leaves. Emergent leaves exposed to airborne inoculum developed severe infection of the lower surface, but not the obscured upper surface. Emergent leaves acquired ontogenic resistance during unfolding, and the upper leaf surface thereby escaped infection. We found no evidence that the pathogen survives winters in New York, USA or Norway within crown tissue. Plants stripped of infected leaves remained mildew-free when forced after overwintering, while mildew colonies commonly developed on emergent leaves of plants not stripped of mildewed leaves. Unsprayed plots established using mildew-free plants either remained asymptomatic or developed only traces of powdery mildew during one growing season, even when located within 100 to 150 meters of severely diseased plots. In summary, our results suggest the following: (i) sanitation, use of disease-free plants, and eradicative treatments could contribute greatly to management of strawberry powdery mildew; (ii) cleistothecia represent a functional source of primary inoculum; and (iii) the common observation of higher mildew severity on lower leaf surfaces may reflect escape of the upper epidermis due to the combined effect of leaf folding and rapid acquisition of ontogenic resistance.

Sammendrag

Målet med dette prosjektet er å utvikle metoder som kan bidra til å redusere risikoen for Fusarium-toksiner i norsk korn. I samarbeid med næringa pågår aktiviteter på to hovedområder: 1 Kartlegging av klimatiske og agronomiske forhold som påvirker angrep av Fusarium og utvikling av mykotoksiner (grunnlag for varsling), samt fokus på dyrkingsteknikk, inkludert sprøyting, som kan redusere risikoen for Fusarium-angrep/toksin-utvikling. 2 Komme fram til analysemetodikk som raskt og rimelig kan måle innhold av mykotoksiner i kornprøver (hurtigmetode) for å identifisere kornpartier med uakseptabelt høyt toksinnivå og dermed avverge at slike partier brukes til mat og fôr.

Til dokument

Sammendrag

The main Avena species that are important weeds of cereal and arable crops include A. fatua L., A. sterilis and A. barbata Pott. All three species have an abscission scar on the grains. A risk assessment of A. fatua L. as an indirect pest in Norway is given in a separate document. For both A. sterilis ssp. macrocarpa and ssp. maxima, and for A. barbata Pott, the potential for entry and establishment in Norway is considered as very low. A. sterilis ssp. ludoviciana (winter wild oats) has a moderate potential for establishment in Norway. The suitability of the environment for A. sterilis ssp. ludoviciana was therefore investigated: Our assessment of the probability of establishment indicates that the climate is not favourable for establishment of A. sterilis ssp. ludoviciana in Norway. A. sterilis ssp. ludoviciana is a problem in southern Europe and central southern England and is mainly a weed in winter cereals. While it is highly likely that the probability of establishment of A. sterilis ssp. ludoviciana has increased in Norway in recent years due to climate change and consequent changes in cultural practices, its probability of establishment in Norway is still low and it is therefore not likely that it will become a weed in Norway under current conditions. However, if the future climate of the PRA area changes, so that winter conditions become similar to conditions in southern England, while the acreage of winter cereal continues to grow, A. sterilis ssp. ludoviciana could become a weed in Norway. A. sterilis ssp. ludoviciana is not present in Denmark where winter cereals are much more widely cultivated, and the climate is more favourable than in Norway. One would therefore expect the weed to establish in Denmark before it will become a problem in Norway