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.
2008
Forfattere
Per Y. SteinsholtSammendrag
Det ble registrert betydelige mengder vekstsprekk i poteter dyrket i 2007. Dette kan ha flere årsaker, ikke bare ujevne vekstforhold. Andre årsaker kan være angrep av virus Y (PVY), skader av plantevernmidler og skader av svartskurv (Rhizoctonia solani)
Forfattere
Jeppe Kolding Lise Haug Sigurd StefanssonSammendrag
Growth, size at maturity, gonadosomatic index (GSI), egg size, and absolute fecundity of Nile tilapia (Oreochromis niloticus) were significantly affected by oxygen levels (1.5 +/- 1.0, 2.8 +/- 1.4, and 6.0 +/- 1.8 mg center dot L-1) in a controlled experiment designed to test the hypothesis (D. Pauly. 1984. J. Cons. Int. Explor. Mer, 41: 280-284) that O-2 is the controlling factor for the transition from juvenile to adult in fish, in general, in the context of phenotypic life history plasticity and "stunting" in tilapias. Size at maturity and the estimated asymptotic size decreased with decreasing O-2 concentration, as predicted by Pauly"s hypothesis. All fish matured at the same age (18 weeks old), which is in contrast to conventional definitions of stunting. This finding challenges the suggested plasticity in age at first maturity for tilapia. The results also challenge the hypothesis that stunting is a unique recruitment mechanism, as the smaller fish in the group with low oxygen concentration produced smaller and fewer eggs than the larger fish in the group with high oxygen concentration.
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Sammendrag
In 1996, a survey on cavity spot started in Norway. Among the Pythium species isolated from the lesions a pathogenic Pythium was found that could not be identified neither by morphological nor by molecular methods (ITS sequencing). This Pythium sp. was repeatedly detected using specific primers developed for this propose and in many cases isolated from cavity spots lesions. The isolates from the new species do not produce zoospores. Oogonia are smooth walled and mostly intercalary with an average size about 20µm. Oospores are aplerotic with an average diameter approximately 17 µm and wall less then 2 µm thick. Antheridia are mostly monoclinous with a sort stalk or sessil, but diclinous antheridia are also common. The modal number of antheridia per oogonium is one or two. Some differences are observed between the isolates studied. Some isolates have a daily growth rate of ca 23 mm on PCA at 25 °C while others have a growth rate around 28 mm. The isolates that grow slower have a tendency to produce one antheridium per oogonium while the isolates with higher growth rates normally produce two. These two groups could also be differentiated based on their ITS sequences which showed 97.8% identity in the 955 base pair rDNA fragment. By using the developed PCR primers it is possible to detect isolates that do not produce the sexual stage in single cultures. These isolates have the same ITS sequence and a similar growth rate and pattern than the fast growing fertile ones.
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Sølvi SvendsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Michelle Fountain Jerry Cross Gunnhild Jåstad David HallSammendrag
Three mirids of horticultural importance in the UK have been studied to ascertain the chemicals involved sexual attraction of males to females. Lygus rugulipennis, the European tarnished plant bug, is an important pest of strawberries and raspberries causing malformation of fruit. Lygocoris pabulinus, the common green capsid, is primarily of concern on blackcurrant, but increasingly damaging on raspberry shoots. Finally, Liocoris tripustulatus, the nettle capsid, causes surface scaring on peppers and aubergines. Ordinarily mirids are controlled with sprays or chlorpyrifos. However, increasing demand for zero residues fruit and the eradication of effective pesticides from IPM programmes is rendering crops more susceptable to attack from mirids. The aim of this project is to develop a long-lived, practical lure, attractive to these species, in order to monitor populations so that effective timings of spray applications can be made to control the pests in fruit crops. It has been demonstrated that adult male L. rugulipennis are attracted to traps baited with live virgin females. Volatiles produced by virgin female L. rugulipennis have been identified as, hexyl butyrate, (E)-2- hexenyl butyrate, and (E)-4-oxo-2-hexenal and elicit electroantennographic (EAG) responses from males in analyses by linked gas chromatography"electroantennography (GC-EAG). We will report results of laboratory and field experiments with blends of the three compounds released from a range of dispensing systems including microcapillary tubes and a piezoelectric dispenser. We have also investigated the effects of various host-plant volatiles on attractiveness and made improvements to trap design and laboratory bioassay procedures.
Forfattere
Gunnhild Jåstad Liv Hatleli Geir Kjølberg Knudsen Miklos TothSammendrag
Både vaksen og larver av vanleg gullauge, Chrysoperla carnea, et på mange artar av skadedyr og er såleis ein viktig predator i mange hagebrukskulturar. I dette studiet vart tre ulike planteluktstoff testa for effkten på egglegging hjå gullauge. resultata viste at ei blanding av desse tre komponentane stimulerte til egglegging hjå gullauge.