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.
2004
Sammendrag
Jordbærsnutebille biter av knopper i jordbær og bringebæ i forbindelse med egglegging. En studie i østlandske jordbærfelter (første- og tredjeårsfelter) viste at billa tidlig i sesongen er mest aktiv på den siden av dobbeltraden som vender mot vest og sør. Senere i sesongen jevner forskjellen innen dobbeltraden seg ut. Det var ikke forskjell på kanten og midten av åkeren i antall avbitte knopper selv om det var flere biller i kanten. Jordbærsnutebilla la som regel ett egg per knopp (66% av avbittte knopper), men det var også vanlig med flere (21%) eller ingen (13%) egg. Avbitte knopper uten egg var som regel urørte av billa (ingen gnag på selve knoppen). Studiet påviste for første gang i litteraturen at billa kan bite av hele blomsterklaser i stedet for en og en knopp. Dette øker skadepotensialet per bille.
Sammendrag
Light inhibits sporulation of Bremia lactucae, and is a component of models for lettuce downy mildew infection periods, but specific intensities and wavelengths involved are poorly understood. We evaluated environmental data and model performance in Norway for two systems, PlantPlus (PP) and Modell-Analys (MA), which are based on a model developed in California. Disease was detected following forecasts issued by both models in 5 of 8 fields. However, forecasted infection periods were not always followed by disease occurrence. Both PP and MA usually called for fewer fungicide applications than a calendar schedule of sprays at 10-day intervals, with no difference in disease suppression among treatments. Date of initial disease varied widely among sites, and may be related, in part, to light intensity and quality at Nordic latitudes, which differ substantially from those of California. Results of subsequent studies on light effects on B. lactucae will be reported.
Sammendrag
I 2003 startet et femårig prosjekt i Norge som omfatter vekstavslutning i potet. Studier av tørråte, forårsaket av Phytophthora infestans, på riset, jorda og på knollene er en viktig del av dette prosjektet. Foreløpige resultater med sorten Folva viste at risdreping 14 dager før høsting reduserte antall sporer i riset og i jorda, og reduserte nivået av knollinfeksjoner sammenlignet med høsting på grønt ris med eller uten sprøyting med fluazinam (Shirlan) 7 dager før høsting. Sprøytingen med fluazinam reduserte imidlertid antall levende sporer i jorda ved høsting sammenlignet med ubehandlet grønt ris. Data fra forsøkene i prosjektet vil bli benyttet til å lage retningslinjer for vekstavslutning i potet blant annet ut fra tørråtesitasjonen i åkeren.
Forfattere
Ricardo Holgado Stig Andersson Janet A. Rowe Christer MagnussonSammendrag
Summary. During the years 1995 to1999 a survey was carried out to study the occurrence of Heterodera spp. in cereals in Norway. Cereal cyst nematodes were found widespread in all the principal cereal growing areas. A formerly unidentified species of cereal cyst nematode, belonging to the "Heterodera avenae complex", is recorded for the first time, heavily parasitising winter rye in the Sandefjord region. Comparative studies, including morphology, protein variability and virulence pattern, of two Norwegian populations with known Swedish H. avenae and H. filipjevi populations confirmed the presence of Heterodera filipjevi (Madzhidov, 1981) Stelter, 1984 in Norway and constitutes a new geographical record. The pathotype tests demonstrated that the two populations were closest to the Swedish pathotype "West".
Forfattere
Ingeborg Klingen Nina Trandem Arnulfo Monzón Falguni Guharay Ragnhild Sand Eduardo HidalgoSammendrag
- Insect pathogenic fungi are important naturally occurring mortality factors of pest insects and mites. - Few studies have been made on natural occurrence of insect pathogenic fungi and the effect of management system in Central America. - One study from Norway confirms that management system (organic compared to conventional) is important to the occurrence and prevalence of insect pathogenic fungi in soil in arable fields. - Another study from Norway indicates the importance of pesticide use on the killing capacity of the mite pathogenic fungi N. floridana to T. urticae. - A master study from Nicaragua showed a higher B. bassiana infection level in L. coffeella with increasing shading. More studies are, however, needed to confirm this trend. - In a PhD project at CATIE Nicaragua, naturally occurring insect pathogenic fungi on key coffee pests and the effect of crop management practices on these fungi is under study. - An ongoing master study will reveal the occurrence of insect pathogenic fungi in soil from different coffee growing systems in Nicaragua and Costa Rica.
Sammendrag
Both insect pathogenic fungi and parasitoids are important for the regulation of insect pests in organic and integrated fruit production. In perennial crop systems, where the pest spends significant periods of time in permanent habitats, biological control is often successful. This is in part due to the stable and robust perennial ecosystem that acts as a reservoir for insect pathogens, parasitoids and other natural enemies of pests. Black cherry aphid (Myzus cerasi) is one of the most important pests on cherries all over the world. However, there are few studies on M. cerasi and insect pathogenic fungi. In this study the occurrence and importance of insect pathogenic fungi and parasitoids as natural enemies of the black cherry aphid was investigated throughout two successive seasons in Norway. Results show that in the first part of the season, from the last part of May to mid July, mostly parasitoids were found in dead aphids. Parasitoids of the following species were found: Ephedrus plagiator and E. persicae. The hyperparasitoids Alloxystra victrix and Dendrocerus sp. were also found in this part of the season, and a few individuals infected with fungi in the order Hyphomycetes (Verticillium lecanii). From the middle of July, fungi in the order Entomophthorales (Entomphthora planchoniana, Erynia neoaphidis and Conidiobolus obscurus) were found in dead aphids. Number of aphids killed by fungi increased towards the end of July. There was, however, a big variation in infection level between trees.
Sammendrag
Insect pathogenic fungi and parasitoids are important control agents of aphids. In a survey in one conventional and four organic apple orchards in Norway insect pathogenic fungi and parasitoids as natural enemies of Aphis pomi and Dysaphis plantaginea were studied weekly in the summer 2002 and 2003. Four species of insect pathogenic fungi in the order Entomophthorales were observed in both apple aphid species: Entomophthora planchoniana, Neozygites fresenii, Erynia neoaphidis and Conidiobolus obscurus. The fungus N. fresenii caused an epizootic on A. pomi in one organic location and seemed to decrease the aphid population during the summer 2002. The highest mortality caused by fungal infection of A. pomi was 39,6 % and 33,3 % of D. plantaginea. Mortality caused by parasitoids was more important in A. pomi than in D. plantaginea and the highest parasitation recorded in A. pomi was 30 %. Four species of primary parasitoids hatched from A. pomi: Binodoxys angelicae, Lipolexis gracilis, Praon sp. and Ephedrus sp. Hyperparasitoids that hatched from A. pomi were: Dendrocerus carpenteri, Alloxysta pleuralis, Phaenoglyphis villosa and Asaphes suspensus. Only one individual of D. plantaginea was parasitized and this parasitoid was Ephedrus persicae.
Sammendrag
In coffee systems, shade management and pests control practices are related to the occurrence of arthropods and micro-organisms, because such practices alter the environmental conditions in the system. The insect pathogenic fungi Beauveria bassiana is used as a microbial control agent against coffee berry borer Hypothenemus hampei, in several countries in America, and it has also been reported to infect the coffee leaf miner Leucoptera coffeella. Only few studies have, however, focused on the natural infection level and the effect of shade and pest management on the dynamic of B. bassiana or other insect pathogenic fungi on key coffee pests. Understanding the dynamic of B. bassiana in the field and its genetic diversity is very important not only to favour its natural occurrence and enhance the natural control, but also to select strains with a good field performance and virulence. The main objectives of this PhD study conducted in Nicaragua are therefore to: a) determine the natural occurrence and infection level of B. bassiana on H. hampei and L. coffeella in unsprayed coffee plantations throughout two successive seasons; b) clarify whether B. bassiana is present as an endophyte in coffee trees, and determine whether B. bassiana injected into coffee plants can establish and persist; c) reveal the effect of shade and use of pesticides on insect pathogenic fungi on H. hampei and in the soil, and d) compare B. bassiana isolates obtained from L. coffeella, H. hampei and the soil at the same and different locations by the use of PCR techniques. The research is being carried out over a period of two years, 2004 and 2005. The natural occurrence and infection level of B. bassiana and the study on endophytic B. bassiana will be studied in unsprayed coffee plantations in the north and the pacific zone of Nicaragua. The experiment on the effect of shade and management practices will be carried out in plots with different pest management practices already established by CATIE in Masatepe, Nicaragua.
Sammendrag
Algesoppen Phytophthora har vore problematisk i lawsonsypress (Chamaecyparis lawsoniana) i fleire år, men bar- og juletreproduksjonen av edelgran har til no vore skåna for denne alvorlege skadegjeraren. I Rogaland vart det i mai 2004 registrert Phytophthora-symptom i eit felt med nobeledelgran (Abies procera) til barproduksjon og i eit juletrefelt med nordmannsedelgran (Abies nordmanniana). I juli 2004 vart Phytophthora også påvist i eit juletrefelt med fjelledelgran i Buskerud. Denne artikkelen er tidlegare trykt i Gartneryrket nr. 7/2004 og i Nålestikka nummer 5/2004, men i dei tidlegare utgåvene er ikkje funn av Phytophthora på fjelledelgran i Buskerud med.
Forfattere
Ricardo Holgado Janet A. Rowe Christer MagnussonSammendrag
Morfologiske karakterer og morfometri til cyster og andre-stadie juveniler for to Heterodera filipjevi-populasjoner fra Norge ble studert og sammenliknet med publiserte data for H. filipjevi. Resultatene fra den morfologiske analysen øker variasjonsbredde til cystekarakterer. Studien gir også ny informasjon om hodets morfologi hos hunnen, cystens kutikula og vulva kjegle, likesom lateralfelt til andre-stadie juvenilen. Disse kompletterende data vil gjøre den morfologiske identifikasjonen av H. filipjevi lettere.