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.
1996
Forfattere
Anne Falk ØgaardSammendrag
Det er ikke registrert sammendrag
Forfattere
Nina JohansenSammendrag
Studies on the population dynamic of Mamestra brassicae (L.) (Lepidoptera: Noctuidae) were conducted during 1988-1992 in order to improve forecasting and control. The influence of temperature on development, fecundity and survival were investigated in climatic chambers, and lower developmental thresholds and thermal requirements were established for the preoviposition period and the immature stages. Pheromone traps were tested in cabbage fields at 5 locations in south-eastern Norway during 1989-1991. The trap catches were low at all locations and years, and the traps could therefore not be recommended for practical monitoring. A degree-day model for prediction of favourable times for assessment of infestation level and insecticide application was developed, validated and implemented. Mortality in the immature stages, and larval dispersal, was investigated in the laboratory and in the field. Highest mortality was found in first instar larvae and in hibernating pupae. The mortality in first instar larvae was probably caused by failure to locate and establish feeding sites and predation, whereas the winter loss probably was caused by unfavourable weather conditions. Life tables for five generations of a natural population of M. brassicae on white cabbage in Ås during 1988-1992 was constructed and analysed. Generation survival was very low, and the key factor was mortality in small larvae. The stage specific mortality appeared to be mainly density-independent. Parasitoids and pathogens were of little importance in controlling the M. brassicae population, although they were more or less persistently present throughout the experimental period. Trichogramma semblidis (Aurivillius) (Trichogrammatidae) was reared from eggs, and Microplitis mediator (Haliday) and Aleiodes (Aleiodes) sp., both Braconidae, were reared from larvae. Erynia virescens (Entomophtorales) was identified in medium and large larvae. Implications of the results in this study for integrated pest management is discussed, and management tactics are proposed.
Sammendrag
A commercial extract of neem (NeemAzal-T) and a simple extract of pulverized seeds extracted in warm water were tested against the cabbage pest Mamestra brassicae L. Gravid cabbage moth females were given a choice between sprayed and unsprayed plants for oviposition during 9 days. Second instar larvae were caged on plants and exposed to a series of neem concentrations (leaf dip assay) and to neem applied to the roots (systemic uptake). Residual activity of NeemAzal-T was tested by caging 2nd instar larvae on plants that had been sprayed with neem solutions one hour to three weeks in advance. Oviposition was reduced to half the number of eggs per plant by the neem treatment. The number of eggs that hatched was not affected by the neem treatment, but development of these larvae was strongly inhibited and all larvae in the neem treatment died within two weeks without reaching 2nd instar. The concentration of the active ingredient azadirachtin-A (the azadirachtin component in NeemAzal-T) needed to protect plants from damage by 2nd instar larvae was 8 "g ml-1. The lethal doses for 2nd instar larvae were determined by probit analysis to be 6.2 and 11.2""g ml-1 for LC50 and LC95 respectively. NeemAzal-T protected plants from damage for at least 3 weeks if applied before oviposition, or at least 2 weeks if applied against 2nd instar larvae. In these studies, neem inhibited oviposition, larval development and feeding, and greatly increased mortality.
1995
Forfattere
A.G. BusethSammendrag
Det er ikke registrert sammendrag
Forfattere
Chr.J. KøhlerSammendrag
Lukket
Forfattere
Chr. J. KøhlerSammendrag
Lukket
Forfattere
A. HovdeSammendrag
Det er ikke registrert sammendrag
Forfattere
G. GoffengSammendrag
Lukket
Forfattere
G. GoffengSammendrag
Det er ikke registrert sammendrag
Forfattere
Chr. J. KøhlerSammendrag
Lukket