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.
2002
Forfattere
Ricardo Holgado S. Andersson J. RoweSammendrag
Cereal cyst nematodes (CCN), Heterodera spp., are common pests of cereal crops in Norway. Fifteen populations were investigated morphologically, through biotests, and through electrophoretic studies, using isoelectric focusing and silver staining of proteins. In the biotest the populations were grouped by their virulence on barley differentials (resistance genes) Varde (Rha), Emir (Rha"E"), Ortolan (Rha1), KVL 191 (Rha2), Siri (Rha2) and Morocco C.I. 3902 (Rha3). Eleven populations expressed themselves as H. avenae pathotype Ha11. These were all fairly similar morphologically and electrophoretically. The biotest further suggested two populations belonging to pathotype Ha12. One of them was morphologically and electrophoretically similar to H. avenae; the other different in both respects, indicating a possible undescribed species. Two other populations appeared to be H. filipjevi, pathotype `West". One population under study was different in all aspects, morphologically, in the biotest and biochemically. Earlier studies in Norway have also indicated the occurrence of CCN pathotype Ha51. Thus, the situation in Norway regarding the CCN is very complicated.
Sammendrag
A method for baiting soil samples with Delia floralis larvae was developed, and a systematic survey was conducted on soils from northern Norway for insect pathogenic fungi, using D. floralis and Galleria mellonella larvae as bait. The occurrence of insect pathogenic fungi in soils from arable fields and adjacent field margins of conventionally and organically managed farms was compared. The study showed a significantly higher occurrence of insect pathogenic fungi in soils from arable fields of organically managed farms. No significant differences in the occurrence of insect pathogenic fungi were, however, found between the field margins of the two cropping systems. Fungal species identified in the study were Beauveria bassiana, Fusarium merismoides, Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was found more frequently when using D. floralis as the bait insect than when using G. mellonella.
Forfattere
Kirsten TørresenSammendrag
Resultater fra to forsøk med ulik jordarbeiding utført i Ås blir rapportert. I det ene forsøket ble ugrasfrø blandet inn i jorda ved start høsten 1993 og deretter ble frøtilførsel forhindret. Jordarbeiding tappet jorda for ugrasfrø og førte til stor oppspiring på ledd pløyd høst eller vår, mens redusert jordarbeiding (høstharving, vårharving, ingen jordarbeiding) hadde flere frø igjen i jorda etter 6 år og totalt mindre oppspiring i perioden 1994-2000 dersom frøformering ble forhindret. I et annet forsøk med fri frøformering i vårkorn var det mer økning fra 1994 til 1999 både i antall oppspirte planter og mengde ugrasfrø i jorda på ledd med redusert jordarbeiding i forhold til pløyde ledd.
Sammendrag
Resultater fra 4-5 langvarige feltforsøk i vårkorn med ulik jordarbeiding og plantevern utført i 1993-2000 presenteres. Avlinga ble opprettholdt og ugras bra bekjempa ved redusert jordarbeiding dersom det ble sprøyta med glyfosat i stubben og med frøugrasmiddel på forsommeren. Ved sein høsting og mye kveke bør glyfosat sprøytes i moden byggåker eller før våronn. Spillkorn (havre) dersom havre var dyrka året før var et problem spesielt på redusert jordarbeiding. Grå øyeflekk kan være et større problem ved høstharving enn ved tradisjonell jordarbeiding, men sjukdommen kan holdes i sjakk enten ved vekstskifte eller soppsprøyting. Havrebladflekk lar seg ikke så lett bekjempe verken med soppmidler eller vekstskifte og kan være et større problem ved direktesåing enn pløying. Redusert jordarbeiding kan føre til økt innhold av Fusarium og mykotoksiner, men klimaforholdene var viktigst for utvikling av disse. Havrebladminerflue og bladlus var mindre vanlig i redusert jordarbeiding enn ved pløying. Nyttedyrfaunaen var noe økt ved redusert jordarbeiding, særlig løpebiller, trolig på grunn av mer ugras.
Sammendrag
Studies were conducted to investigate potential interactions between brassicaceous plants, the isothiocyanates they produce and insect pathogenic fungi. Studies in vitro showed that 100 ppm of 2-phenylethyl isothiocyanate completely inhibited growth of Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was significantly inhibited by 10 ppm 2-phenylethyl isothiocyanate, but not by 1 ppm. M. anisopliae was not inhibited by 10 or 1 ppm 2-phenylethyl isothiocyanate. The effect of freshly grated rutabaga on virulence of M. anisopliae to Galleria mellonella larvae was also tested, resulting in reduced infection by M. anisopliae. To study the effect of plants in the Brassicaceae under more field-like conditions fungi were added to soil without plants or at the bases of two different plant species, Barbarea vulgaris and Eruca vesicaria sativa. Soil was sampled at 5, 10 and 15 days to determine the concentration of colony forming units (CFUs). Treatments with plants did not have fewer CFUs than the control. Instead significantly fewer CFUs resulted when M. anisopliae was added to pots with soil only than to pots with plants. There were no significant differences between the two plant species in the number of CFUs at day 5. For days 10 and 15, however, significantly more M. anisopliae CFUs were found in pots containing E. vesicaria sativa than B. vulgaris. T. cylindrosporum was less affected by the different treatments than M. anisopliae. Our studies demonstrated that while isothiocyanates can inhibit insect pathogenic fungi in Petri dishes, when using a more realistic fungus/plant/soil microcosm no fungal inhibition was found.
Forfattere
Christer Magnusson P. Sagberg Bonsak HammeraasSammendrag
The soil conditioner, VEAS-Biosolids, is produced through compression, heating and vacuum drying of sewage sludge at the VEAS wastewater treatment plant in Slemmestad, Norway. The sanitation efficacy for potato cyst nematode (PCN), Globodera rostochiensis and wild oat, Avena fatua, was evaluated for the final production step, the combined thermal filter press and vacuum dryer Germ carriers, each carrying three nylon bags with 20 nematode cysts and one bag with 100 seeds of wild oat, were placed in three filter presses. Germ carriers were either exposed to sludge for 4 days, or kept dry before the test. The test pathogens were exposed to pressures of up to seven bars at 35 ºC, followed by heating to 80 ºC and vacuum at "0.92 bar during continued heating. Nematode vitality was studied by recording juvenile hatch, by vitality staining with New Blue R, and by recording nematode development on susceptible potato. Viability of wild oat was examined by tetrazolium test. There was a 100% efficacy in the sanitation of PCN and wild oat. For both organisms pre-exposure to sludge seemed to reduce vitality and viability.
Forfattere
Christer Magnusson L. Thijsen Ricardo HolgadoSammendrag
Meloidogyne chitwoodi may be introduced into Norway through plant material and soil. The nematode may easily establish on common crop plants. During the growing season two generations are expected to develop in southern Norway, while conditions in the central parts would allow for the development of one generation. M. chitwoodi starts to develop at 5ºC. Planting and sowing in Norway starts when soil temperatures reach around 4ºC. The use of plastic tunnels to increase soil temperature is a common practice in early potatoes and vegetables, and would enhance nematode development. M. chitwoodi requires 600-800 degree days (DD) to complete one generation from the time of planting, and 500-600 DD for subsequent generations. These temperature sums are commonly recorded in potato growing areas of Norway. Qualitative damage on potato tubers would require the reinfection and development of the second generation, and is expected in the southern areas. Qualitative damage on carrots does not require reinfection, and is expected also in central parts. The possibility that the nematode could cause damage to other vegetables and to cereals is an additional concern that supports its status as a quarantine pest organism.
Sammendrag
Rotstokkròte som er årsaka av algesoppen Phytophthora cactorum (Leb. & Cohn) Schroet., vart påvist i jordbær første gong i 1992 i Noreg. Til no er det i sortane Elsanta, Inga, Jonsok, Korona, Nora, Polka og Zefyr at rotstokkròte er funnen. Sjukdomen, også kjent under namna kronròte og rothalsròte, har gitt stor skade i enkelte felt. Artikkelen er en revidert utgave av Fagnytt 4/95.
Sammendrag
The susceptibility of Delia floralis eggs, neonates and larvae and the susceptibility of Galleria mellonella and Mamestra brassicae larvae to seven different Norwegian isolates of the insect pathogenic, hyphomycetous fungi Tolypocladium cylindrosporum, Metarhizium anisopliae and Beauveria bassiana, were investigated. Metarhizium anisopliae isolate ARSEF 5520 was highly virulent to G. mellonella larvae and caused 100% mortality when tested at a concentration of 3.6x106 conidia/ml. The same M. anisopliae isolate was not virulent to D. floralis larvae. Isolates of T. cylindrosporum, were equally virulent to G. mellonella and D. floralis causing up to 36.0% mortality of larvae. It is suspected, however, that the use of grated rutabaga as a food source in the D. floralis bioassay reduced the fungal virulence of both M. anisopliae and T. cylindrosporum to D. floralis. Among three T. cylindrosporum isolates tested at a concentration of 1.0x107 against eggs of D. floralis none of them reduced the hatching percentage. One isolate, ARSEF 5525 did, however, significantly reduce the longevity of neonates. Beauveria bassiana isolates ARSEF 5510 and ARSEF 5370 tested at a concentration of 1.0x107resulted in M. brassicae mortality levels of 70.0 and 55.0% respectively. The B. bassiana isolate ARSEF 5557, however, was not virulent to M. brassicae. Among the three isolates tested against M. brassicae the two virulent isolates produced a red pigment, probably oosporein, when cultured in Sabouraud dextrose agar.
Forfattere
Håvard EikemoSammendrag
To investigate the variability in Phytophthora cactorum, 44 isolates from different geographic locations were collected. The isolates originated from various plant species, but the majority were crown rot and leather rot isolates from strawberry. DNA was extracted from all isolates, and examined by AFLP using seven different primer combinations. The resulting dendrogram revealed that isolates from crown rot in strawberries from all locations showed a very low degree of variation, and were clearly separated from the more variable leather rot isolates (of strawberry fruits) and isolates from other hosts. The separation of isolates with and without the ability to cause crown rot was confirmed in a pathogenesis test on strawberry plants. Several methods of screening strawberry cultivars for resistance to Phytophthora cactorum were tested and evaluated in this study. The methods involved both fresh and cold stored plants, and either mycelium on agar or a zoospore suspension was used to inoculate wounded or unwounded plants. Also inoculation of detached leaves and inoculation of plants in vitro were tested as possible methods of screening for resistance. Several of these methods discriminated well between cultivars, but they varied in reproducibility and accuracy. The preferred method was inoculation of unwounded, cold stored plants with a zoospore suspension. It was the least laborious method, and the results were reproducible when the same cultivars were tested several times over several years. Sammendraget er redigert.