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
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
Linda Gordon Hjeljord Gunn Mari StrømengSammendrag
In the search for effective antagonists of Botrytis cinerea, the leap from the laboratory to the field often produces disappointing results. An ideal antagonist screening protocol would be efficient and reproducible, while taking into consideration environmental parameters known to affect activity of the interacting microorganisms. We are developing a screening procedure which is based on the biology and infection requirements of B. cinerea. Our model system is based on the infection of strawberry blossoms. B. cinerea requires exogenous nutrients in order to infect plant tissues. Therefore we analyzed nectar and pollen extracts from newly opened strawberry flowers, as these are known to be especially susceptible to infection. These extracts were found to contain 1-2 mg/ml each of fructose and glucose. We adjusted the sugar content of potato dextrose agar to a final concentration of 2 mg/ml of fructose and glucose (PDFA) and investigated antagonistic interactions between different fungal isolates on media differing in nutrient content (PDFA, PDA, 1/4 PDA, and vegetable juice agar). Isolates were inoculated on these media in mixtures and separately, and in different concentrations. We found that a number of isolates were able to inhibit mycelial growth of B. cinerea in standard dual cultures (hyphal interactions or antibiosis between meeting colonies), especially on nutrient-poor media, but also on PDFA. However, only a few isolates were able to prevent growth of B. cinerea when the conidia were mixed and co-inoculated on PDFA. We also tested the effect of constant and fluctuating temperatures in the range of 10-30oC on interactions between B. cinerea and strawberry phylloplane isolates of Epicoccum nigrum, Ulocladium spp. and Cladosporium sp. on different substrates. The effect of the fluctuations varied with isolates and appeared to depend on the amplitude of the deviation from the mean. Finally we measured oxygen consumption rates of B. cinerea and various antagonists, to see whether this was related to antagonism toward B. cinerea. Several isolates showing good antagonistic activity under these controlled conditions were tested further on detached strawberry flowers, as well as in field trials the summer of 2004. Results of these tests on isolates of species known for their antagonism toward B. cinerea will be discussed. This investigation is part of a directed search for biocontrol antagonists on the basis of their ecophysiological characteristics relative to infection requirements of B. cinerea.
Forfattere
Frances M. Dewey Kristof Capieau Linda Gordon Hjeljord Gunn Mari Strømeng Chris DanksSammendrag
Det er ikke registrert sammendrag
Forfattere
Bjørn MoltebergSammendrag
Fra den siste avsluttede forsøksserien i gras til grøntanlegg er det foreløpig godkjent fire nye utenlandske grassorter. Enda flere lovende norske og utenlandske sorter fra den siste og tidligere prøvinger blir trolig godkjent i tiden framover. Godt helhetsinntrykk og god markdekking er viktig for godkjenningen. Samtidig skal sorten være tett, ha god farge og liten høydetilvekst. Med andre ord rangeres de sorter som tar seg godt ut, samtidig som de krever lite stell, høyest. Blant de nye, godkjente sortene er det rødsvingelsorten "Alice", sølvbunkesorten "Barcampsia" og engkveinsorten Leirin som skiller seg mest ut og som trolig er best egnet til bruk på idretts- og golfarenaer.
Forfattere
Bjørn Molteberg Jan TangsveenSammendrag
Forsøk med fangvekster har nå gått i fire vekstsesonger (2000-2003). Forsøkene har vært en del av det fireårige prosjektet "Bruk av fangvekster i kornomløp", som er gjennomført av Planteforsk Apelsvoll forskingssenter. Avlingsreduksjonen i kornet vil variere mellom år. Normalt vil den ligge på 3-7 % i bygg. Ut fra vekst og utvikling av de prøvde arter og sorter, kan følgende sies: Italiensk toårig raigras regnes som en sikker fangvekst i hele landet og er enkel å etablere, men det kan konkurrere sterkt med kornet. Det kan være relativt store forskjeller i konkurranseevne mellom sorter av dette raigraset. Engelsk (flerårig) raigras er godt egnet som fangvekst i hele landet. Det er mindre aggressivt og konkurrerer mindre med kornet enn italiensk raigras. Under normale forhold har dette raigraset god utvikling og grasproduksjon som fangvekst utover høsten. Forskjeller i konkurranseevne, vekst og utvikling på høsten mellom sorter er av mindre betyding. Timotei kan fungere som fangvekst på hele Østlandet og delvis i Trøndelag, men vil ikke være like sikker som raigras. Den kan konkurrere relativt hardt med kornet, hvis kornbestandet er noe tynt. Opp til 10-12 % avlingsreduksjon kan forekomme i bygg, men normalt vil den ligge på 1-2 %. Arten regnes som enkel å etablere. Engsvingel vil være en svært usikker og lite egnet fangvekst. Den kan eventuelt fungere i enkelte år i områder nær kysten, som for eksempel i Vestfold. Arten konkurrerer lite med kornet. Hundegras er i likhet med timotei interessant, kan fungere som fangvekst på hele Østlandet og delvis i Trøndelag, men vil ikke være like sikker som raigras. Arten konkurrerer lite med kornet. Hybridraigras og raisvingel vil fungere som fangvekst på linje med engelsk raigras. Raisvingel vil imidlertid ha noe høyere pris pr. kg. Et godt etablert fangvekstdekke (underkultur) reduserer proteinprosenten i kornet. En må være forsiktig med delgjødsling (proteingjødsling) til korn der en har sådd fangvekster, spesielt raigras, da denne grasarten vil gi kraftig vekst ved en slik delgjødsling. Delgjødsling for å redusere legdefaren kan imidlertid være en fordel. Normal såmengde (1,0 kg/daa) reduserer kornavlingene noe, men til gjengjeld sikrer det etableringen av fangvekstene i forhold til redusert mengde (0,5 kg/daa). I praksis vil 0,7-0,8 kg/daa av raigras være å anbefale.
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.
Forfattere
Bjørn Molteberg Frank EngerSammendrag
Dette er en forvaltningsoppgave som gjennomføres på oppdrag fra Mattilsynet (tidligere Landbrukstilsynet) ( www.mattilsynet.no ). Målet er å framskaffe resultater for godkjenning av nye sorter for opptak på norsk sortsliste. ( http://www.mattilsynet.no/multimedia/archive/00006/Sortsliste_6758a.pdf ). Prøvingen er en kontinuerlig, ikke tidsavgrenset prøving. Flerårige arter legges ut to ganger med tre registrerings- og høsteår etter hvert utlegg. Ettårige arter prøves i tre år. Artene blir som hovedregel prøvd i fem distrikter, Østlandet, Fjellbygdene, Vestlandet, Midt-Norge og Nord-Norge. I 2003 var det sorter av følgende arter med i prøvingen: Timotei, engsvingel/raisvingel, engelsk (flerårig) raigras, hundegras, strandrør, engrapp, rød- og hvitkløver. Totalt var det 64 sorter i prøving, ingen av disse var ferdig prøvd. I tillegg var det med 41 målesorter. Sorter som var ferdig prøvd i 2003 kommer i tillegg til de nevnte 64. Disse er presentert i egen rapport. (Grønn kunnskap e Vol. 8 Nr. 124 - 2004).