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.
2011
Sammendrag
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Forfattere
Britt I.F. Henriksen Oscar Hovde BerntsenSammendrag
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Sammendrag
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Forfattere
Britt I.F. HenriksenSammendrag
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Sammendrag
Organic fields are often assumed to have less pests and more beneficials than conventionally managed fields. We monitored 12 Norwegian strawberry fields, six organic and six conventional, by sampling leaves two times per year in 2002-2003. Young folded leaflets were visually inspected for eggs and adult females of strawberry mite (Phytonemus pallidus fragariae), and mature leaves were used for extraction of mobile stages of two-spotted spider mite (Tetranychus urticae). The spider mites were examined for infection of the mite-pathogenic fungus Neozygites floridana. Predatory mites (Phytoseiidae) were recorded on both leaf types, and the females mounted and identified. Soil was also sampled from each field, to study the natural occurrence of entomopathogenic nematodes. All samples were taken 0-13 metres from the border vegetation. Both pest mites tended to be more abundant in conventional than in organic fields, while the number of phytoseiid mites was very low in both growing systems. Nevertheless, three phytoseiid species were recorded for the first time in Norway: Amblyseius rademacheri Dosse, Neoseiulus kodryensis (Kolodochka) and Neoseiulus reductus (Wainstein). N. floridana infection found in T. urticae females varied from 0-19%, and was higher in 2002 than in 2003. The fungus was recorded at least once in all 12 fields, and there was no consistent difference between the two growing systems. In 2002 there was a significant negative correlation between % T. urticae with N. floridana hyphal bodies found in the first sampling and the number of T. urticae present in the second sampling about four weeks later. Beneficial nematodes (mostly Steinernema) tended to occur in more of the organic than in the conventional soil samples. To sum up, both pests (T. urticae and P. pallidus) and one of the beneficial groups (entomopathogenic nematodes) seemed to conform to the expected difference between organic and conventional fields. There are many possible mechanisms related to the differences in pesticide and fertilization regimes that could lead to such a pattern. For the two remaining beneficials (N. floridana and Phytoseiidae) we could not find a consistent correlation between abundance and growing system.
Sammendrag
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Sammendrag
Glen Ample is the main raspberry cultivar in Norway. This cultivar is very susceptible to the raspberry leaf and bud mite Phyllocoptes gracilis, and serious damage on both leaves and fruits are common. The only documented control measure available has been fenpyroximate (Ortus/ Danitron), a substance that can only be used once per growing season, which is not sufficient to keep P. gracilis below damaging population levels. Nor can it be used by organic growers. In a search for alternative control measures we conducted trials with rapeseed oil (emulsified with soft soap) and sulphur (Thiovit Jet) in heavily infested fields. The effect was measured by assessing leaf damage and counting mites overwintering in the buds. The results imply that post harvest spraying with vegetable oils or sulphur targeting overwintering females in the buds is a very valuable component of a management strategy for the leaf and bud mite in ‘Glen Ample’.
Sammendrag
The strawberry blossom weevil (Anthonomus rubi) is a small univoltine weevil severing the flower buds of strawberry and some other species of Rosaceae in order to provide for its offspring. The damage made by the weevil in Norwegian strawberry fields is increasing as chemical control is proving difficult and large numbers of weevils are observed in yet more districts. To develop new strategies to control the weevil, a better understanding of its biology is needed. Most studies of A. rubi have focused on the period when bud damage is done, whilst less is known about the ecology and behaviour at other times of the year. The literature on overwintering habits indicates that in the UK A. rubi leaves the strawberry field to overwinter, while elsewhere in Europe they may stay in the field. In a Norwegian project we used emergence traps and laboratory inspection of individual plants to search for weevils in the late autumn and early spring. In fields with weevil problems, we found significant numbers of A. rubi, typically 1-5 per plant (average of 10 plants) shortly before snow fall, and similar numbers early in the spring. The overall sex ratio was close to 1:1. We also found large numbers of overwintering weevils in plants that had been terminated with glyphosate, indicating that weevils were not repelled by dying plants as overwintering habitat. This considerable presence of weevils in the crop throughout the year could increase the chance of succeeding with alternative methods like microbiological control or mass trapping. It also implies that terminated (glyphosate-treated etc) fields should be ploughed on cool days in the autumn (A. rubi cannot fly at low temperatures) to bury the weevils, and not be left alone till late in the spring for weevils to escape.
Forfattere
Atle Wibe Anna-Karin Borg-Karlson Jerry Cross Lene SigsgaardSammendrag
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Forfattere
Liv Solemdal Gunnar KvammeSammendrag
St. Olavs Hospital i Trondheim har videreført sin satsing på økologisk mat, flere år etter at kjøkkenet deltok i et fireårig prosjekt for innføring av 30 % økologisk mat. I tillegg til forbruket av økologiske varer, kan det vises til en rekke andre positive effekter av arbeidet. Maten har fått en styrket posisjon ved at sykehusets ledelse har vedtatt en ernæringsstrategi. Den økologiske andelen er forankret i ledelsen og inngår i de årlige planene til sykehusets driftsorganisasjon "Mat og Cafe".