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.
2016
Sammendrag
Fusarium and Microdochium may cause seedling blight and poor germination of cereal seeds. However, indications of poor survival of Fusarium in seed and improved germination after some months of storage have been observed. A study was carried out to investigate if seed storage can contribute to improved seed quality. Samples from seed lots of barley, oats and spring wheat were tested for germination capacity and Fusarium /Microdochium infection frequencies a few days after harvest, and after 5, 12 and 15 months of storage. In barley, the average germination percentage increased slightly, from 92% at harvest to 95% after five months of storage. In oats, the average germination percentage increased from 82% to 85% during the first five months. In spring wheat, the average germination percentage was reduced from 81% at harvest to 67% after five months. In barley and oats, average Fusarium /Microdochium frequencies were reduced during storage, with the highest reduction observed during the first five months (from 50% to 37%, and from 60% to 46%, barley and oats respectively). In spring wheat, no significant reduction in average infection level was recorded (58% at harvest, 50% after 15 months of storage). There was however, variation between seed lots in all three cereal species in both germination percentage and Fusarium /Microdochium frequencies during the storage period. It is concluded that storage of barley and oats seeds for 5 months after harvest may in some cases increase the seed quality and thereby meet the certification requirements of minimum 85% germination.
Sammendrag
Aphids in cereals are an important problem in Europe. Entomopathogenic fungi in the Phylum Entomophthoromycota are among their natural enemies. Under certain conditions, they can cause epizootic events and control pest aphid populations. This epizootic development is affected by many abiotic and biotic factors such as aphid species and their host plant (including weeds within the crop), fungal species and isolates, and temperature. Studies from Denmark, UK, Slovakia and suggest that the genus Pandora is the most prevalent fungal pathogen of the English grain aphid (Sitobion avenae). Which fungal species that is the most prevalent in populations of the other important aphid species in cereals in Europe, the Bird cherry-oat aphid (Rhopalosiphum padi), is less clear. We chose, however, to use Pandora to assess the biological control potential of Entomophthoromycota against aphids in cereals and to produce data that might be used in a pest-warning model incorporating the effect of this natural enemy. This was done by conducting laboratory studies on the virulence of two Pandora isolates (collected in the same field) on R. padi and Myzus persicae at three temperatures (12, 15 and 18◦C). M. persicae is a polyphagous aphid that may be present on weeds. It can be an alternative host for Pandora and hence might also affect the epidemic development of Pandora in aphids that are cereal pests. Our preliminary results show that R. padi is more resistant to the tested Pandora isolates than M. persicae. The two Pandora isolates had different virulence in the two aphid species tested. The temperature did not influence the virulence.
Sammendrag
The two-spotted spider mite, Tetranychus urticae, is a serious pest of numerous crops worldwide. Sustainable management solutions for T. urticae include predators and entomopathogens. Neozygites floridana is a naturally occurring obligate fungal pathogen of T. urticae and can cause declines in T. urticae populations. The purpose of this study was to determine whether releasing the predatory mite Phytoseiulus persimilis into T. urticae populations has the potential to increase transmission of N. floridana and accelerate the development of an epizootic. This is the first study quantifying the effect of P. persimilis on transmission of N. floridana to T. urticae in a controlled microcosm study. Our results show that introducing P. persimilis into T. urticae, populations increased the proportion of T. urticae infected with N. floridana. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted. We suggest that releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone.
Forfattere
Lars Olav BrandsæterSammendrag
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Juliana PerminowSammendrag
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Tage ThorstensenSammendrag
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Jorunn BørveSammendrag
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