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
Forfattere
Ricardo HolgadoSammendrag
In 1955 the potato cyst nematode was recorded for the first time in Agder. This detection produced the initial legislation of PCN control, and was implemented based on the statutory regulation of 1916. Since 1956 PCN was given quarantine status in infested agricultural land and home gardens. Official controls of certified seed potatoes started in 1939. Each year about 3000 soil samples are analyzed for PCN to clear areas for certified seed potato production. These areas are so far free of PCN. The total acreage with seed potatoes in 2009 was 813.7 Ha. Extensive surveys started in 1955; and were carried uninterrupted until the end of the 1990ties. These surveys included producing potato agricultural land and home gardens. In 2009 a new national survey program for the principal potato districts has started, the surveys is aimed to update the PCN occurrence. The surveys will continue during the subsequently years until all major potato areas will be cover. Statutory regulations for PCN from 1956-2010 to Support to Norwegian Food Safety Authority The regulations have without doubt contributed in preventing PCN infestations in the seed potato areas, and probably also prevented further spreading of wPCN and virulent yPCN as each the find has been placed under quarantine. Permanent grass as a statutory regulation in home garden plots may have contributed to reduce the spread of wPCN to commercial fields. The regulations have most probably made possible the early reduction in use of chemical fumigants, organophosphates or carbamate nematicides. These chemicals have not been used since the early 1970s. The domestic production of seed potato has been kept free of PCN by frequent inspections and analyses for more than 50 years. The fact that farmers are not allowed to import seed potatoes adds to the level of security. New project Studies on the biology of potato cyst nematodes (Globodera spp.) under Nordic conditions for improving management and regulation in Norway. Major goal is to increase the scientific basis for amending the management system for PCN, Globodera spp under Nordic conditions.
Forfattere
Ricardo Holgado Christer MagnussonSammendrag
In Norway PCN was recorded in 1955. This resulted in extensive surveys and implementation of statutory rules. Regular surveys until the 1990s revealed PCN to occur in 6406 properties. The first statutory regulation for PCN appeared in 1956, and prohibited the introduction and spread of PCN with soil and plant materials. Before the early 1970:ties control strategies included the use of nematicides (fumigants, organophosphates and carbamate) and resistant potato cultivars. The distribution of species and pathotypes is of crucial importance for mangement. The yellow species Globodera rostochiensis (yPCN) occurs in the pathotypes Ro1, Ro2, and Ro3, while the white species G. pallida (wPCN) has been detected in the pathotypes Pa1, Pa2 and Pa3. The most common pathotype Ro1 constitutes 98% of total finds. Recently the detections of wPCN and yPCN Ro3 in ware potato fields have increased. Today non-virulent G. rostochiensis is managed with crop rotations using non-host crops and alternating susceptible and resistant potato. The use of certified seed potato is important. Detection of G. pallida or virulent G. rostochiensis results in statutory regulation (at least 40-years ban on growing potato). Generally Norwegian potato cultivars have the resistance gen, Gro-1 (H1) from Solanum tuberosum ssp. andigena. In Norway great emphasis has been placed on documenting freedom of PCN in areas for certified seed potatoes. In 2009 a national survey of ware potato land was initiated. The use of early potato and Solanum sisymbriifolium as trap crops, and the significance of micro-organisms antagonistic to PCN are considered in current research. Norwegian regulations have prevented PCN infestations in the seed potato areas, and reduced spread of wPCN and virulent yPCN. A better prognosis of rates of decline in PCN numbers and infectivity in fields could allow for a reduction in the quarantine period and improve the economy of farmers and enterprises.
Forfattere
Ricardo Holgado Christer MagnussonSammendrag
Cyst nematodes, Heterodera spp. are known world-wide as parasites of cereals and grasses. Norwegian surveys have revealed that nematodes belonging to the H. avenae complex occur throughout the country; our studies have combined morphology, protein variability (IEF), bio-tests and internal transcribed spacers (ITS3 and ITS5) for the identification of Heterodera populations. Our results showed some divergences between techniques in species identity of some of the studied populations H. avenae is the most common species followed by H. filipjevi (Holgado et al., 2009).. Several populations of H. filipjevi west did not reproduce in oat differentials. In this case both the morphology and protein patterns rather indicated these populations to belong to H. pratensis. In this study a population from Brekstad differed from all other populations in its morphology, and the protein pattern was close to H. mani. This population was collected from barley, and in the pathotype test it was virulent on several barley cultivars. Mathews, 1971reported that H. mani did not reproduce on cereals while (Cook, 1982) indicates that some barley cultivars can serve as hosts. Surprisingly the ITS studies indicated the Brekstad population to be close to H. avenae. This population is in many ways strikingly different from H. avenae, and this result may indicate a need to revise the present gene library of H. avenae. It also demonstrates the need for using several techniques in species identification. In our study the least degree of divergent results on nematode identity is between morphology and IEF.
Forfattere
Ricardo HolgadoSammendrag
Cyst nematodes, Heterodera spp. are known world-wide as parasites of cereals and grasses. Norwegian surveys have revealed that nematodes belonging to the H. avenae complex occur throughout the country; our studies have combined morphology, protein variability (IEF), bio-tests and internal transcribed spacers (ITS3 and ITS5) for the identification of Heterodera populations. Our results showed some divergences between techniques in species identity of some of the studied populations H. avenae is the most common species followed by H. filipjevi (Holgado et al., 2009).. Several populations of H. filipjevi west did not reproduce in oat differentials. In this case both the morphology and protein patterns rather indicated these populations to belong to H. pratensis. In this study a population from Brekstad differed from all other populations in its morphology, and the protein pattern was close to H. mani. This population was collected from barley, and in the pathotype test it was virulent on several barley cultivars. Mathews, 1971reported that H. mani did not reproduce on cereals while (Cook, 1982) indicates that some barley cultivars can serve as hosts. Surprisingly the ITS studies indicated the Brekstad population to be close to H. avenae. This population is in many ways strikingly different from H. avenae, and this result may indicate a need to revise the present gene library of H. avenae. It also demonstrates the need for using several techniques in species identification. In our study the least degree of divergent results on nematode identity is between morphology and IEF.
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.
Forfattere
Halvor Solheim Martti VuorinenSammendrag
During a survey conducted in August 2009 in northern Norway, symptoms typical for red band needle blight (1) were observed in four young Scots pine (Pinus sylvestris) stands. The stands, less than 15 years old, were located in humid sites near rivers in Bardu and Målselv municipalities, Troms County. Many of the oldest needles (2- to 3- years-old) in the lower part of young trees were partially or completely brown, but still attached, and red bands could be observed. Aggregations of conidial stromata were often seen in the red bands. Conidia were hyaline, smooth, thin walled, and filiform, 1.9 to 2.6 μm wide and 12 to 36 μm long....
Forfattere
Helge SjursenSammendrag
I foredraget ble oppbyggingen av ugrasplansjene gjennomgått. I en plansje er alle stadiene i livsyklusen illustrert, fra den første frøplanten til modent frø. Særlig er rotsystemet rikt illustrert. Ved hver deltalj i en plansje er det notert en bokstav, som en kan finne igjen med egne forklaringer i teksthefter. I foredraget ble det framhevet de 10 flerårige artene som ellers ble omtalt under ugrasseminaret: krushøymole, vanlig høymole, byhøymole, lyssiv, knappsiv, hundekjeks, kveke, hestehov, åkertistel og åkerdylle
Forfattere
Helge SjursenSammendrag
Frømelde hører til den biologiske gruppen sommerettårige. Den voksne planten er 20-60 cm høy med svak, greinet pålerot. Stengelen er oftest noe nedliggende, eller opprett, sterkt greinet, firkantet og glatt, ofte noe rødlig. Bladene er stilkete, ovale eller eggformet-elliptiske, med kileformet grunn og helrandet. Blomstene er samlet i knipper i mange, greinete, kvastformete aks i bladhjørnene og i toppen av greiner og stengler. Formeringen og spredningen skjer bare ved frø. Forekommer på dyrket mark, gjødsel- og komposthauger, avfallplasser, veikanter og strandkanter. Opptrer som ugras i hager og i alle slags åkerkulturer, særlig hagebrukskulturer. Mottiltak som for meldestokk.
Forfattere
Helge SjursenSammendrag
Følblom hører til den biologiske gruppen flerårig stedbundne med trevlerot. Den voksne planten er 10-60 cm høy med trevlerot. Planten har hvit melkesaft. Stengelen er oftest gaffelgreinet og bladløs, bortsett fra et lansettformet høyblad i hvert greinhjørne. Bladene er grunnstilt og i rosett, avlange, buktfinnete eller grovt bukttagget. De er mørkegrønne og nesten glatte på oversiden, lysere på undersiden. De gule blomsterkorgene, 2-3 cm i diameter, sitter enslige i toppen av stengel og greiner. De tungeformete kronene er oftest rødaktig på undersiden. Blomsterskaftet er noe fortykket og skjellkledd opp mot korgen. Forekommer i både dyrket og udyrket grasmark, langs veier og jernbaner, og på tomter og ballastplasser. Finnes også i høyfjellet (egen varietet), og vokser på alle slags jordarter, men liker seg aller best på leirjord. Opptrer som ugras først og fremst i eng og beite. Mottiltak: Som for løvetann. Ellers er følblom lett å bekjempe med ugrasmidler som inneholder MCPA.