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.
2010
Forfattere
Ricardo HolgadoSammendrag
The correct identification to species and pathotype is of crucial importance for the kind management and regulations to be imposed in Norway as G. pallida and G. rostochiensis species are quarantine pests regulated in the national plant health legislation. Identification is in accordance with the EPPO diagnostic protocol. Morphology, Iso electric focousing and molecular methods are used. Today, non-virulent G. rostochiensis is managed by crop rotation, while infestations by G. pallida or virulent G. rostochiensis results in at least 40-years ban for growing potato.
Forfattere
Ricardo Holgado Christer MagnussonSammendrag
In 1955 the potato cyst nematode (PCN) was recorded for the first time in Norway. This detection resulted in extensive surveys and measures were implemented based on the statutory regulation of 1916. The first statutory regulation for PCN was put in power in 1956, and later amended in several occasions. These regulations prohibit the introduction and spread of PCN with soil and plant materials. Early control strategies included the use of chemical fumigants and resistant potato cultivars in infested fields, and surveys detected new infestations which were placed under quarantine regulations. The recognition of G. rostochiensis and G. pallida, their pathotypes enabled a more precise use of resistant cultivars. Commercial chemical fumigants, organophosphates or carbamate nematicides have not been used in Norway since the early 1970s. Today, non-virulent G. rostochiensis is managed by crop rotation, while infestations by G. pallida or virulent G. rostochiensis results in at least 40-years ban for growing potato. Most Norwegian potato cultivars have the resistance genes, Gro-1 (H1) from Solanum tuberosum ssp. andigena. During the preceding decades great emphasis has been placed on documenting freedom from PCN in the production of certified seed potatoes, certified seed potato are used in combination with crop rotations using non-host crops, alternating susceptible and resistant cultivars. These are important control measures, but not easy to implement in Norway due to restricted acreage suitable for long rotations. The safe use of resistant potato cultivars requires a better knowledge on the presence of species and pathotypes in potato fields. In order to improve our information of the occurrence of PCN a new national survey program for the principal potato districts has started. These surveys will complemented by information generated from a new research project dealing with: studies of the virulence of selected PCN populations, decline rates of nematode field population densities and infection potential over time of populations from fields placed under quarantine regulations. studies on the occurrence and pathogenicity of microbial antagonistic parasitic on PCN, and their potential of future management of PCN, the safe use of early potato cultivars as a practical control method, and the potential for using Solanum sisymbriifolium as a trap crop, distinguish the degree of resistance of selected potato varieties available on the Norwegian market, and initial studies of the PCN-Potato-Pathosystem. These expected results of this project possibly will improve the management of PCN, and may alleviate present regulatory restrictions.
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
S.radicicola is a parasite of barley and grasses like Poa annua and P.pratensis. The life cycle of a Norwegian population of S.radicicola (Poa-race) is studied in the laboratory by inoculating newly germinated P.annua (cv. Leif) with 140 juveniles from field collected galls and keeping the plants at 25˚C and 16 hrs light period. Juvenile stages are separated based on genital development. The first stage (J1) has 1 cell, while the following stages J2, J3 and J4 has 2, 3 and 4 (or more) cells in their genital primordia. J1 (L = 310-350μm) moults in the egg and J2 (L = 330-400μm) is the hatching stage. Nematodes emigrating from field collected galls were all J3:s (L = 360-430μm), and moulted outside the gall to J4 (L = 210-500μm). The first stage to appear in newly formed galls is large J4 (L=500-870 μm), which moults within 5 days to adult (L=820-1980 μm). Egg-laying starts within 13 days and eggs hatch after 22 days. Juvenile development in eggs starts at 5˚C, and 640 degree days are required for completing one generation corresponding to about 30 days at 25˚C. This means that in Norway S.radicicola may have up to 3 generations per year. The fact that J3 exit the galls and the large J4 is the first stage present in newly formed galls makes us speculate that the induction of gall formation occurs from outside by pre-infective J4, which later infects and develop inside the gall. Key Words: Root gall nematode, Subanguina radicicola, Poa annua, life cycle, Norway
Forfattere
Christer MagnussonSammendrag
The recent spread of pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is a concern to Nordic countries. Since PWN may exist in trees free of symptoms its distribution becomes unclear. Commodities like pulpwood, particle wood (PW) and wood packaging material (WPM) could have hidden infections. Pulpwood offers obvious risks of transmission due to a possible presence of both PWN and its vectors (Monochamus spp.). Generally, PW is considered to pose a low theoretical risk due to absence of vectors, and WPM no risk if heat treated. Transmission of PWN from infested wood to trees has been demonstrated, and a recurrent use of PW on sports tracks may during one forest cycle result in transmission. PWN can survive for long periods in wood, and reported limited heat treatment capacities indicate that infested WPM already may circulate within the EU. In the Nordic region, pallet wood is a popular fuel and is stored at summer houses where direct contact with trees could cause transmission. In Nordic locations establishment of PWN is expected to cause damage only in hot summers. Even in a warmer climate the damage at least in a 50 yrs perspective is expected to be small, but costs of nematode control will be very high. In a short perspective effects on Nordic exports are small, but in a longer perspective new outbreaks of pine wilt disease in Europe could change export markets. Key Words: Pinewood nematode, Europe, trade risks, Nordic region
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
The spread of the pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is a threat to 36 million ha Nordic coniferous forests. In spite of a strict phytosanitary regulation of wood imports, the volumes and an unclear distribution of PWN could result in an introduction into the Nordic region. In the present climate expression of pine wilt disease is expected only in hot summers. Hence, the detection of PWN in the Nordic area is likely to remain unnoticed for a considerable period of time. In Fennoscandia more than 9000 samples have been analyzed from risk areas and risk commodities. The focus often has been on the breeding substrate of the vector insects in the genus Monochamus. A recent study on a simulated introduction in Norway (Økland et al in print) indicates that 14 years may elapse before detection by the present level of 400 samples annually. It was demonstrated that an earlier detection of PWN provided by an annual sample volume of 10 000 samples would still not be sufficient for successful eradication of PWN by 3 km radius clear-cuts. So, large sampling volumes and strict import regulations for PWN are highly important for the Nordic area. Økland, B.O. Skarpaas, M. Schroeder, C. Magnusson, Å. Lindelöw & K. Thunes 2010. Is Eradication of the Pinewood Nematode (Bursaphelenchus xylophilus) Likely? An Evaluation of Current Contingency Plans. Risk Analysis in print Key Words: Pinewood nematode, Nordic area, sampling, eradication, regulation
Forfattere
Christer MagnussonSammendrag
Det er ikke registrert sammendrag
Sammendrag
VKM"s Panel 9 gives the following main conclusions of part 2 of the risk assessment: 1) Under the present climatic conditions, and if no control measures are taken, an introduction of PWN to the PRA area will not cause increased pine tree mortality. The level of uncertainty of this assessment is low. 2) Assuming the IS92a climate change scenario for the period 2000-2049 (RegClim), which involves a ~2 ºC temperature increase by the end of the period, an introduction of PWN to the PRA area will, if no control measures are taken, cause a minor increase in pine tree mortality (300 trees per year on average). The mortality can become larger if the temperature increases more than 2 ºC, and will gradually increase with time after 2049 due to spread of PWN. The level of uncertainty of these assessments is medium to high. 3) Any effects of PWN presence in the PRA area on export of wood and wood products will be of little importance. The level uncertainty of this assessment is low. 4) It will be almost impossible to eradicate PWN once it has been introduced to the PRA area. The level of uncertainty of this assessment is low. 5) The cost of a single eradication event as described in the preliminary contingency plan for the PRA area is approximately 700 mill. NOK. Due to expected spread, the total cost of eradication attempts following one introduction event will be approximately 2000 mill. NOK for the first 50 years. The level of uncertainty of these assessments is medium. 6) The negative effects of the control measures on the environment will be major. The level of uncertainty of this assessment is low.