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
Authors
Jr. I Delalibera V.W. Wekesa Karin Westrum V. Duarte da Silveira T. Rodrigues de Castro S.S. Nilsen Ingeborg KlingenAbstract
The mite-pathogenic fungus Neozygites floridana and N. tanajoae are important natural enemies of spider mites and are good candidates for microbial control. To be able to succeed in using Neozygites for the microbial control of spider mites we need to understand the factors that affect a Neozygites epidemic development. Studies have therefore been conducted with Brazilian and Norwegian isolates of these fungi to reveal the effect of abiotic (temperature, rainfall, humidity, light, pesticides) and biotic factors (host plant, presence of predators) on the fungal performance and epizootic development in cassava green mite, tomato red spider mite and twospotted spider mite populations. For Brazilian isolates, rainfalls do not seem to have an apparent impact on disease progression. Microclimatic humidity seems, however, to be a critical factor. When placed on microscope slides, these two fungi only sporulate at RH≥95%, while N. floridana-killed cadavers of the twospotted spider mite placed within the boundary layer of the abaxial side of a leaf sporulated also at 90% RH. The temperature optimum of Brazilian and Norwegian isolates varies and Brazilian isolates can sporulate at temperatures as low as 13°C but the highest production of capilliconidia occurs at 21-25°C. A Norwegian N. floridana isolate tested produces the highest numbers of primary conidia at 13°C and 18°C while 23°C resulted in a lower production. Our studies also show that performance of different N. floridana isolates may vary with light duration and intensity. In integrated pest management systems, Neozygites needs to be compatible with chemical pesticides. Our studies show, however, that several fungicides affect N. floridana negatively. Our studies have also shown that performance of Neozygites vary with host plants.
Abstract
The two spotted spider mite Tetranychus urticae is known to overwinter as hibernating females, and these partly inactive females may harbour Neozygites floridana. N. floridana is a fungal natural enemy of spider mites. The aim of this study was therefore to investigate whether N. floridana may be present inside living hibernating females of T. urticae throughout the winter season, and if so, in what prevalence and what stage of its fungal life cycle. Hibernating T. urticae females were investigated for the presence of fungal structures throughout one winter (October 12, 2006 to February 19, 2007) in field-grown strawberries in a cold climate in Norway (min. ambient temp -15.3oC). The study confirmed that N. floridana survived the winter as a semilatent hyphal body infection, protected inside live hibernating females. The beneficial fungus N. floridana is therefore ready to develop and sporulate as soon as climatic conditions permits, resulting in early season infection of T. urticae. An early-season infection of N. floridana that may result in the control of T. urticae in strawberries is important, since T. urticae is known to cause reductions in strawberry yield at much lower population levels in early season than in late season. For N. floridana to control T. urticae populations early in the spring, factors important for sporulation and dissemination of the fungus needs to be favoured. The adapted use of pesticides, especially fungicides might therefore be very important at this time of the year.
Abstract
The use of Chinese cabbage as a trap crop where insect pathogenic fungi may prolifereate has been tested in a series of push-pull strategy experiments both in the laboratory and in the field. The pest species studied are the cabbage- and turnip root fly (Delia radicum and D. floralis). In a dual choice laboratory experiment, both healthy and Entomophthora muscae inoculated D. floralis were tested for choice of plant for oviposition. The choices were 1) Broccoli against Broccoli 2) Chinese cabbage against Broccoli 3) Broccoli against Broccoli under sown with clover 4) Chinese cabbage against Broccoli under sown with clover. In a semi-field pilot study with Broccoli and Chinese cabbage the choice between main - and trap crop for healthy and inoculated flies, as well as fungal transmission between flies over time, was studied. A pilot field study has also been performed to investigate the overall effect of using Chinese cabbage as a trap crop as well as studying the spatial distribution of Delia eggs in a cabbage field. The results from the dual choice experiment and both pilot studies indicates that using Chinese cabbage as a trap crop is a promising strategy for the management of D. radicum and D. floralis, both as a oviposition attractant and as a trap crop where insect pathogenic fungi may proliferate and kill the adult flies.
Authors
Liv Guri Velle Vigdis VandvikAbstract
Det er ikke registrert sammendrag
Authors
Liv Guri Velle Liv S. Nilsen Vigdis VandvikAbstract
Det er ikke registrert sammendrag
Authors
Nina JohansenAbstract
Topics: a) What is pesticide resistance?, b) History of pesticide resistance c) Concequenses of pesticide resistance, d) Resistance risk factors, e) Pesticide Resistance Management, f) Regulation of the placement of pesticides on the market, g) National action plan, h) International cooperation and coordination of pesticide resistance management.
Authors
Nina JohansenAbstract
Topics •How and why do arthropods use light? •Current and emerging light technologies in greenhouse production •Research done on artificial light (AL) and IPM •What do we know about direct and indirect effects of AL on greenhouse pests and natural enemies •Approaches for utilization of AL in IPM •Knowledge gaps and future research.
Authors
Annichen Smith Eriksen Annichen Smith EriksenAbstract
Temaer: Integrert plantevern i veksthuskulturer, brukerrettet prosjekt for å øke bruken av integrert plantevern, erfaringer fra rådgiving om integrert plantevern i veksthus, suksesskriterier- og historier, motivasjon, utfordringer.
Authors
Agnar KvalbeinAbstract
Introduction to Bioforsk Turfgrass Research Group Correct fertilization - healthy turf 1. Basic principles 2. Demand driven fertilization 3. Late fall fertilization 4. Potassium in the fall? 5. Phosphate or phosphonite?
Authors
Agnar KvalbeinAbstract
Outline 1. Introduction 2. Soil physics 3. Greens and approach areas 4. Surface water management 5. Sand-caping 6. Vakuum drainage 7. Fairwaydrainage