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Free-living plant-parasitic nematodes (free-living PPN) appear to be an increasing problem in Norwegian agriculture and their efficient management is required. Methods of efficient nematode management have been sought for personnel involved in farmer’s advisory and among farmers. In order to clarify the nematode situation in different agricultural crops a pilot project for surveying free-living PPN was conducted during the growing seasons 2016 and 2017. The Norwegian Agricultural Extension Service were involved in selecting major crops and selected representative areas for sampling. Complementary to the survey was that the samples should be collected form crops showing symptoms of nematode damage. Nematode damage occurs where large populations of nematoder are present in fields and shows as patches of poor plant growth........

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Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the pathway and planning measures for enhancing biosecurity.

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Kartleggingsprogrammet for 2016 startet i april og sluttet 31. desember 2016. Programmet omfattet potetprodusenter som hadde dyrket poteter i 2015 og søkt om produksjonstilskudd for slik produksjon. Prøveuttaket foregikk delvis i felt hvor det var dyrket poteter i 2015. I tillegg ble det tatt prøver fra sorteringsjord i mottaksvirksomheter. I 2016 det ble undersøkt totalt 34 jordprøver i programmet. Kartleggingsprogrammet omfattet fylkene Møre og Romsdal (22 jordprøver fra mottaksvirksomheter), Nordland (10 jordprøver fra felt), Troms (2 jordprøver fra felt). Det ble ikke funnet PCN i prøvene fra Møre og Romsdal, Nordland og Troms. I kartleggings program for 2014, 2015 og 2016 det ble ikke funnet PCN i prøvene fra Norland, Troms og Finnmark fylkene. Dette viser at Nordland Troms og Finnmark fylkene er så langt fri for potetcystenematoder, og dette antyder at PCN ikke finnes i nordlige områder med potet produksjon. Fra 2009 til 2016 ble det analysert 18846 jordprøver, (13951 fra felt, og 4895 fra mottaksvirksomheter), i 17817 prøver PCN ble ikke funnet. Potetcystenematoder ble funnet i 995 jordprøver som representerer 5,2 % av totalet. I kartleggingsprogrammet for 2009 - 2016 hvit PCN (Globodera pallida) ble funnet i 92 prøver. I disse 92 prøver, blanding av G. rostochiensis og G.pallida ble funnet i 73 prøver. Dette kan indikere at tiltak som er satt i verk for å begrense spredningen har hatt effekt. Siden 1955 lovregulering for PCN har som målsetning å hindre introduksjon og spredning av PCN med jord og plantemateriale, samt å sikre et kontrollert bruk av resistente potetsorter for å unngå resistensbryting. PCN-Forskriftene har også gjort det mulig å unngå bruken av kjemiske fumiganter, organofosfater eller karbamater (nematicider). Nematicider har ikke vært brukt i potetproduksjon i Norge

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Skogens helsetilstand påvirkes i stor grad av klima og værforhold, enten direkte ved tørke, frost og vind, eller indirekte ved at klimaet påvirker omfanget av soppsykdommer og insektangrep. Klimaendringene og den forventede økningen i klimarelaterte skogskader gir store utfordringer for forvaltningen av framtidas skogressurser. Det samme gjør invaderende skadegjørere, både allerede etablerte arter og nye som kan komme til Norge som følge av økt handel og import. Eksempler på begge er omtalt i denne rapporten som presenterer resultater fra skogskadeovervåkingen i Norge i 2016........

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Nematodes as limiting factors in potato production in Norway Plant parasitic nematodes associated with potato feeds on roots and/or tubers. At least 68 species, representing 24 genera of have been found associated with potato. Since nematodes generally attack underground plant parts, there are no reliable foliar symptoms to show that nematodes may be the major cause of poor growth and reduced tuber yields. Potato roots damaged by nematodes may show the presence of lesions, females/cysts or galls. After a few weeks, however, roots may be attacked by other pathogens such as bacteria and fungi, and the original damage by nematodes may not be obvious. Therefore, nematode damage often may have been attributed to other factors. There are no estimations for potatoes yield losses in Scandinavia due to nematodes, however, in the United Kingdom, it is estimated that 9 % of the potato crop is lost annually because of the potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida, and it is reasonable to assume that this percentage is also applicable to Scandinavia. However, if we consider the possible additional effects of other nematode species occurring in Norway, yield reductions could be as high as 20%. Besides direct yield losses, some nematodes affect tuber quality. Yield losses depend on the pathogenicity of the species of nematode, the nematode population density at planting, the susceptibility and tolerance of the host and by a range of environmental factors. In Norway, potato cyst nematodes (G. rostochiensis and G. pallida) are by far the most important nematodes in potato. Other important nematodes include root-lesion nematodes (Pratylenchus spp.), stubby root nematodes (Trichodorus spp. and Paratrichodorus spp.) and stem and tuber nematodes (Ditylenchus spp.). Nematodes considered less important include root knot nematode (Meloidogyne hapla) and needle nematodes (Longidorus spp.). In Norway, potato cyst nematodes (Globodera rostochiensis and G. pallida) are quarantine pests subjected to regulations. PCN infestations result in costly production systems and loss in sales value of farms. Their occurrences restrict acreage available for potato production as in some cases legislative regulations forbid potato production or make the production more difficult and more expensive. Furthermore societal consequences by far exceed yield losses. It is also compulsory to sample the soil for seed potato production to document freedom from PCN. When PCN is present in the field complete eradication is not possible. Effective management requires reliable information on virulence, decline rates of population densities and infectivity in soil. It is also crucial to know what conditions or practices increase these decline rates. Today in Norway, non-virulent G. rostochiensis is managed by crop rotation, while infestations by G. pallida or virulent G. rostochiensis pathotypes capable of breaking the resistance in potato cultivars in current use results in a 40-years prohibition for growing potato in the infected field. Root-lesion nematodes (Pratylenchus spp.) cause damage to the roots and induce scabby to sunken lesions on tubers. Stubby root nematodes (Trichodorus spp. and Paratrichodorus are nematode vectors of Tobacco Rattle Virus they causes the symptom called “Spraing” in tubers. Occasionally stem and tuber nematodes (Ditylenchus spp.), have been reported as problems both in field and storage, especially when weeds are not well controlled. Management strategies aim to prevent nematode multiplication and hence protect the potato crop from damage. An efficient method of controlling nematodes as Ditylenchus spp. and root-lesion nematodes is black fallow, but this may be difficult to achieve in many cases.

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Introductions of the pine wood nematode (PWN), which causes Pine Wilt Disease (PWD), have devastating effects on pine forests in regions with susceptible host trees under suitable climate conditions. Norwegian authorities have proposed a contingency plan if PWN is detected in Norway. We compare the costs of implementing this plan with the costs of further spread and damage of PWN under two climate change scenarios: present and the most likely future climate. With the present climate, PWD will not occur in Norway. Under climatic change, the cost of PWD damage is approximately 0.078–0.157 million NOK (0.01–0.02 million Euros) estimated as net present value with 2 and 4% p.a. discount rate. In contrast, the corresponding costs of implementing the suggested contingency plan will be 1.7–2.2 billion NOK (0.2–0.25 billion Euros). These costs are caused by reduced income from industrial timber production and the costs of the eradication measures. Costs related to reduced recreation or biodiversity are expected to be very high, but are not included in the above estimates. Many of the factors in the analysis are burdened with high uncertainty, but sensitivity analyses indicate that the results are rather robust even for drastic changes in assumptions. The results suggest that there is a need to revise the current PWN contingency plan in Norway.

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Plant parasitic nematodes associated with potato feed on roots and/or tubers. About 70 species, representing 24 genera, have been reported from potato. Since nematodes attack underground plant parts, there are no reliable foliar symptoms to show that nematodes may be the major cause of poor growth and reduced tuber yields. Potato roots damaged by nematodes may show lesions, abnormal proliferation of lateral roots, emerging white females and brown cysts. Nematode attacks may render plants vulnerable to other pathogens, so disease caused by microorganisms may have nematodes as an etiological component. Therefore, nematode damage may often have been attributed to other factors. In Scandinavia, potato cyst nematodes (Globodera rostochiensis and Globodera pallida) are by far the most important nematodes on potato. In Norway, the cost of compensations schemes due to imposed statutory regulations of potato cyst nematodes may some years exceed the compensation for any other pests or diseases organism in agriculture. Other important nematodes include root lesion nematodes (Pratylenchus spp.), stubby root nematodes (Trichodorus spp. and Paratrichodorus spp.), and potato rot and stem nematodes (Ditylenchus spp.). Root knot nematode Meloidogyne hapla is considered less important. Meloidogyne chitwoodi and Meloidogyne fallax are not known to be present in Nordic countries. In the control, crop rotations using non-host crops, alternating susceptible and resistant potato cultivars, are an important control measure. However, the use of resistant potato cultivars requires knowledge of the species and pathotypes present in the field.

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The European Commission requested the Panel on Plant Health to deliver a scientific opinion on the phytosanitary risk of plants (other than fruits and seeds) of Pinus pinea and of the genera Chamaecyparis, Cryptomeria and Juniperus for the spread of pine wood nematode (PWN) via movement of infested plants or untreated plant products or by supporting natural spread of PWN in conjunction with European species of the vector. The Panel analysed the data submitted by Portugal regarding surveys on the Tróia Peninsula where P. pinaster and P. pinea co-occur, and the related laboratory results of Naves et al. (2006) on feeding and oviposition preferences of Monochamus galloprovincialis. The Panel also undertook a comprehensive review of the literature. The zero infestation of PWN recorded on P. pinea on the Tróia Peninsula was not significantly different from the result for P. pinaster, because of the small P. pinea sample. Hence, the conclusion that P. pinea is not a host plant for PWN is not supported by the data submitted, principally because of low statistical confidence arising from the few P. pinea trees present. Moreover, the limited presence of P. pinea in the study areas means that the results are representative neither of the Tróia Peninsula nor of other parts of Portugal. Naves et al. (2006) recorded some oviposition by M. galloprovincialis on P. pinea, but less than on other hosts. No differences in feeding of M. galloprovincialis on P. pinaster and P. pinea were detected, thus potentially allowing PWN transmission to trees by this route. The available information regarding the genera Chamaecyparis, Cryptomeria and Juniperus as potential hosts of Monochamus spp. and PWN suggests overall a low susceptibility to PWN or its vectors; the uncertainty concerning PWN is high and would require supplementary research. © European Food Safety Authority, 2012  

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Abstract Introductions of the pine wood nematode (PWN), which causes Pine Wilt Disease (PWD), have devastating effects on pine forests in regions with susceptible host trees under suitable climate conditions. Norwegian authorities have proposed a contingency plan if PWN is detected in Norway. We compare the costs of implementing this plan with the costs of further spread and damage of PWN under two climate change scenarios: present and the most likely future climate. With the present climate, PWD will not occur in Norway. Under climatic change, the cost of PWD damage is approximately 0.078- 0.157 million NOK (0.01-0.02 million Euros) estimated as net present value with 2 and 4% p.a. discount rate. In contrast, the corresponding costs of implementing the suggested contingency plan will be 1.7-2.2 billion NOK (0.2-0.25 billion Euros). These costs are caused by reduced income from industrial timber production and the costs of the eradication measures. Costs related to reduced recreation or biodiversity are expected to be very high, but are not included in the above estimates. Many of the factors in the analysis are burdened with high uncertainty, but sensitivity analyses indicate that the results are rather robust even for drastic changes in assumptions. The results suggest that there is a need to revise the current PWN contingency plan in Norway. Keywords: Bioeconomics, boreal forest damage, Bursaphelenchus xylophilus, climate change, impact assessment, stochastic modelling.

Sammendrag

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.

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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.

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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.

Sammendrag

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.

Sammendrag

Some species of plant parasitic nematodes restrict severely the productivity of crops. In Nordic countries nematodes are often overlooked as factors explaining crop failure. This neglect may relate to a 2/3 reduction of personnel in Nordic nematology which has happened since 1994. The resulting decrease in the lecturing and training of students threatens recruitment, scientific development and awareness of plant nematodes as parasites. This is serious since damage from nematodes can only be reduced by correct management of populations. This will contribute to soil health and a sustainable production. Potato cyst nematode (PCN), Globodera spp., is economically the most important pest attacking potato. It is difficult to detect in the fields, and 20 years may elapse before damage is noticed. The cost for managing PCN is high since management relies on intensive monitoring and regulation. PCN is mainly managed by crop rotations with non-hosts crops grown between alternating susceptible and resistant potato. Among cereal cyst nematodes (CCN) the most common species are Heterodera.avenae and H. filipjevi. Both species have pathotypes differing in their host preferences. Under Nordic conditions serious damage seems to appear with about 40-years intervals. For CCN, correct knowledge of species, pathotype and population density is essential in designing crop rotations. Optimal rotations may allow for yield increases of up to 1 t/ha. In Norway and Sweden damage from root knot nematodes (RKN), Meloidogyne hapla on vegetables and M. naasi on cereals, has been detected more frequently in recent years. RKN have their largest importance in continental and southern Europe, and the increase in field damage seen in the Nordic area may be a first sign of climate change. It is likely that also damage from other nematodes will increase with rising temperatures. Research cooperation between Nordic countries seems urgent to meet the future challenges in plant nematology.

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The capacity for research and services in Plant Nematology has decreased much in the last 20 years. This is happening world wide and in the Nordic region the staff in Nematology has been reduced by 2/3 since 1994.  We have already entered a situation where the capacity in most countries is insufficient to meet actual needs for research and development, as well as the needs for diagnostic services.  Today the critical mass of the Nordic region is dangerously low.  The scientific support required in decision making demonstrates a need to ensure the engagement of a sufficient number of nematologists. The present decrease in lecturing and training activities threatens recruitment and development. This situation can only be solved by an increase in research collaboration between Nordic countries.

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Nematoder (rundormer) er mest kjent som parasitter i dyr, mennesker og planter. Størstedelen av nematodene (ca. 60 %) lever imidlertid fritt i jord og vann og er ikke parasitter. De er ørsmå, gråhvite, «markliknende» organismer som er viktige for omdanning av organisk materiale og sirkulering av næringsstoffer i jorda. De fleste jordlevende arter er < 1 mm og lever i vannfilmen rundt jordpartikler og røtter.

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In the Nordic countries the total forest area is 67 million hectars, with conifers covering 38 milllion hectars. The Nordic standing crop of conifer wood is about 5 million m3, with an almost equal share of pine (Pinus sylvestris) and spruce (Picea abies). Because of this large and precious forest resource, the recent spread of pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is of great concern to Nordic countries. The expression of pine wilt disease requires summer temperatures higher than normal for Scandinavia. However, in the area of the recent outbreak in Galicia in Spain, temperatures seem modest, with mean values for July and August at or just above 20oC. Climate change may push the Nordic area into warmer conditions. Available models suggest that damage to Nordic forests is expected to be small in a 50 years perspective. Long-term models are scarce, but in view of pine tree production cycles of up to 120 years, mortality may occur more frequently within one or a few forest generations. Since PWN may exist in trees free of wilt symptoms its distribution in Europe becomes unclear. Monitoring of the pest in Nordic forests requires sampling of cutting waste with signs of activity from vector insect in the genus Monochamus. In the Nordic area more than 9000 samples have so far been analyzed from risk areas and risk commodities. A recent simulation PWN spread in Norwegian forests indicates that 14 years may elapse before detection by the present level of 400 samples annually. We are convinced that large sampling volumes and strict import regulations are vital strategies for keeping the Nordic area free from PWN.

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A major challenge facing agricultural scientists today is the need to secure food for an increasing world population. The World Bank in 2008 estimated a population increase of 35% by 2050. Reducing yield losses caused by pathogens of agricultural crops is one measure that can contribute to increased food production. Plant-parasitic nematodes are often important constraints on crop production; they can cause extensive damage and substantial yield losses. Nematode attack can also predispose plants to attack by other pathogens either through mechanical damage or on a genetic basis. These interactions between nematodes and other pathogens in disease complexes increase yield losses. The degree of damage can also be dependent on host plant and age. In addition, environmental and climatic conditions influence the nematode density. Damage that results from nematode attack affect not only the feeding cell, but reduces also the capacity of the root system, to take up nutrients and water. The decreasing availability of agrochemicals makes the situation complicated as the use of nematicides has been the principal tool for nematode management over the past decades. Nematode management strategies are targeted at preventing nematode multiplication and hence protect the crop from damage. In absence of nematicides the growing of resistant varieties is the most cost-effective and successful means of management. Combined with knowledge of the biology life-cycle, and the effects of cultural practices like crop rotation, organic amendment, growing resistant cultivars may minimize the effect of plant parasitic nematodes. To meet these challenges interdisciplinary research is needed.

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The pinewood nematode (PWN) is one of the worst tree-killing exotic pests in East-Asian countries. The first European record of establishment in Portugal in 1999 triggered extensive surveys and contingency plans for eradication in European countries, including immediate removal of large areas of conifer host trees. Using Norway as an example, we applied a simulation model to evaluate the chance of successful eradication of a hypothetical introduction by the current contingency plan in a northern area where wilting symptoms are not expected to occur. Despite a highly variable spread of nematode infestations in space and time, the probability of successful eradication in 20 years was consistently low (mean 0.035, SE 0.02). The low success did not change significantly by varying the biological parameters in sensitivity analyses (SA), probably due to the late detection of infestations by the survey (mean 14.3 years). SA revealed a strong influence of management parameters. However, a high probability of eradication required unrealistic measures: achieving an eradication probability of 0.99 in 20 years required 10,000 survey samples per year and a host tree removal radius of 8,000 m around each detection point.

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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.

Sammendrag

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.

Sammendrag

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

Sammendrag

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

Sammendrag

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

Sammendrag

In Nordic countries organic farming started as bio-dynamic farms in the 1930s, and still in the 1970s only a small number of farms were organic. Since then the acreage of organic farming has increased and in 2007 Sweden had 222 268 ha (7.9%), Finland 147 557 ha (6.4 %), Denmark 147 482 ha (5.4%), Norway 43 033 ha (4.7%) and Iceland 4 684 ha (0.27%). In northern areas the short vegetation period combined with low temperatures reducing mineralisation causing nutritional deficit may restrict yields. As mineral fertilizers are prohibited in organic farming, plant nutrition and yield depend on proper microbial activity for nutrient cycling. Plant parasitic nematodes (PPN) reduce plant growth, while microbivorous nematodes (MBN) increase nutrient accessibility. Nitrogen fixating legumes, used to improve soil nitrogen levels, may increase densities of PPN to levels causing crop damage. Management of PPN in organic farming relies on knowledge of population dynamics, damaging thresholds and cultural methods like weed control, sanitation, mulching, crop rotation and resistant cultivars. Keeping PPN below damaging levels and supporting beneficial MBN to improve mineralisation would increase yields and improve quality of organics crops in northern areas. Management of MBN is less well understood, but may be of crucial importance for organic farming in northern areas.

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. 

Sammendrag

Soil samples from a growth depression in potato (Solanum tuberosum) cv. Saturna field in Grue, eastern Norway, yielded large numbers of root lesion nematodes, Pratylenchus penetrans. Yield of potato 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 per 250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. Pratylenchus penetrans was present in roots, underground stems, stolons and tubers. In tubers, nematodes were detected inside cross-lesions typical of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. On potato cv. Saturna grown in a green-house, 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. Pratylenchus 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.

Sammendrag

Norwegian cereal cyst nematode populations were studied by biochemical, molecular, morphological and bio test techniques. H. avenae occurred in the pathotypes, Ha11, Ha12, and H. avenae Våxtorp. H. filipjevi was recorded as pathotype West. H. avenae (Ha 11) and H. filipjevi West were the most common species. Thirty barley, 23 oat and 6 of summer wheat cultivars on the Norwegian market were tested for their resistance against H. avenae (Ha11), H. avenae Våxtorp and H. filipjevi West. Resistance against Ha11 was found in 5 barley, 3 oat and in 1 wheat cultivar. Resistance against H. avenae Våxtorp was not present in barley, but 4 oat and 1 wheat cultivar were resistant. For H. filipjevi West resistance was not detected in wheat, but in 6 barley and 13 oat cultivars. A management system based on careful nematode identification and knowledge on resistance of cultivars were set in operation in the county of Vestfold. As a result farmers have improved average yields by 1000 kg /ha. By implementing this program in full the county of Vestfold could make an annual gain of 800 000 €. In perspective of increasing damage from CCN world-wide the correct identification of species and the recognition of their genetic variability is instrumental for successful control.

Sammendrag

Norwegian cereal cyst nematode populations were studied by biochemical, molecular, morphological and bio test techniques. H. avenae occurred in the pathotypes, Ha11, Ha12, and H. avenae Våxtorp. H. filipjevi was recorded as pathotype West. H. avenae (Ha 11) and H. filipjevi West were the most common species. Thirty barley, 23 oat and 6 of summer wheat cultivars on the Norwegian market were tested for their resistance against H. avenae (Ha11), H. avenae Våxtorp and H. filipjevi West. Resistance against Ha11 was found in 5 barley, 3 oat and in 1 wheat cultivar. Resistance against H. avenae Våxtorp was not present in barley, but 4 oat and 1 wheat cultivar were resistant. For H. filipjevi West resistance was not detected in wheat, but in 6 barley and 13 oat cultivars. A management system based on careful nematode identification and knowledge on resistance of cultivars were set in operation in the county of Vestfold. As a result farmers have improved average yields by 1000 kg /ha. By implementing this program in full the county of Vestfold could make an annual gain of 800 000 €. In perspective of increasing damage from CCN world-wide the correct identification of species and the recognition of their genetic variability is instrumental for successful control.

Sammendrag

Cereal cyst nematodes (CCN), Heterodera spp. are well-known world-wide as parasites of cereals. In Scandinavia H. avenae is the most common species and occurs in the pathotypes, Ha11 and Ha12, and the additional pathotypes H. avenae-Knislinge, H. avenae-Ringsåsen and H. avenae-Våxtorp. H. filipjevi, which occurs in the two pathotypes, "East" and "West" is less common than H. avenae.  For several years it has been known that resistance to cereal cyst nematodes may be found in some commercial cultivars, although no conscious breeding for resistance has been attempted. In 2004 and 2005 a majority of cereal cultivars on the Norwegian market were tested for susceptibility/resistance towards H. avenae pathotype Ha11, H. avenae pathotype "Våxtorp" and H. filipjevi pathotype "West" The test program included 30 cultivars of barley, 23 cultivars of oats and 6 cultivars of summer wheat. Resistance against Ha11 was found in 5 barley, 3 oat cultivars and in 1 wheat cultivar. Resistance against H. avenae pathotype "Våxtorp" was not present in barley, but 4 oat cultivars and 1 wheat cultivar were resistant. For H. filipjevi "West" resistance was not detected in wheat, but in 6 barley and 13 oat cultivars. Obviously the variability in CCN is larger than generally anticipated. In Norway management systems based on careful nematode identification and good knowledge of suitable resistant cultivars are in operation. Resistant barley is generally recommended when nematode populations are high due to its high tolerance compared to resistant oats. Farmers implementing this program have reported increased cereal yields of in average 1000 kg /ha. It has been calculated that by implementing this program in full the county of Vestfold could make an economic gain of 800 000 € annually. In perspective of increasing damage from CCN world-wide the recognition of its genetic variability is instrumental for successful control.

Sammendrag

The Altiplano is one of the most elevated areas populated in the world. At 3 500 - 4 000 m, low temperature, and other climatic conditions impose severe limitation for vegetable production. The average temperature levels and the daily amplitudes is a function of altitude, so vegetables are mainly produced in rustic greenhouses. NGOs in the Andean region have recommended cultivation of vegetables for consume and commercialization to enhance the well being of farmers. Plant parasitic nematodes or poor management have limited the vegetable production in rustic greenhouse. The Catholic University of Bolivia has a network of rural campuses "Unidades Académicas Campesinas" (UAC) for academic and practical teaching. Bioforsk has been involved in developing and strengthening the scientific basis in Plant Nematology in UAC-Tihauanaco. Farmers in Tiahuanaco experienced decreasing vegetable yields. In 1999 soil and plant samples from potato and other Andean crops were collected from greenhouses. All samples contained plant-parasitic nematodes. Twenty-one genera of plant-parasitic nematodes were found. The most frequent were potato cyst nematodes Globodera rostochiensis and the false root-knot nematode Nacobbus sp. (54 %), followed by lesion nematodes Pratylenchus spp. spiral Helicotylenchus sp. and Tylenchus sensu lato (41 %), ring nematodes Criconemella sp. (34 %), stunt nematodes Tylenchorhynchus spp. (29 %) and root-knot nematodes Meloidogyne sp. (19 %). The study indicated that plant-parasitic nematodes have a large impact on vegetable production. The knowledge of nematode species are of fundamental importance in the design of efficient management strategies, that would allow farmers to keep nematode population densities at levels below the threshold of economic damage. Management with crop rotation and the use of cultivars with resistance are important control measures, but require detailed information on the occurrence and density of nematode species.

Sammendrag

Phytophthora ramorum S. Werres, A.W.A.M. de Cook & W.A. Man in‘t Veld is a newly described Phytophthora-species which is considered to be relatively recently introduced to both USA and Europe from an unknown area, or areas, of origin. The pathogen has a wide host range and causes a complexity of disease symptoms generally grouped into three categories: canker, foliage lesion, and dieback. In Europe the pathogen has been reported in 21 countries, Norway included; predominantly on ornamental plants in nurseries, but also outside nurseries in gardens and semi-natural environment, most often on rhododendrons. The Norwegian Food Safety Authority needs a risk assessment of the pest as basis for an evaluation of a future phytosanitary risk management of P. ramorum, including whether the organism should be regulated as a quarantine pest in Norway. On this background the Norwegian Food Safety Authority, in a letter of 22nd August 2008, requested a pest risk assessment of P. ramorum from the Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM). The pest risk assessment was adopted by VKM"s Panel on plant health (Panel 9) on a meeting 24th June 2009. VKM"s Panel 9 gives the following main conclusions of the risk assessment: 1) P. ramorum is present but not widely distributed in Norway, and the pest is under official control. The outdoors surveys of P. ramorum in Norway have not been conducted systematically over the whole country, and some uncertainty therefore still remains regarding the current distribution of P. ramorum in the PRA area. 2) The overall probability of entry of P. ramorum into Norway and the overall probability of establishment of P. ramorum in Norway are both rated as high with low levels of uncertainty; 3) In the absence of statutory control the probability for P. ramorum to be spread quickly in the PRA area by trade of host plants for planting is rated as high. The uncertainty of this assessment is low; 4) The part of the PRA area where presence of P. ramorum might result in economically important losses (the endangered area) is assessed to be most of the country of Norway, except where the climate is predicted to be unfavourable for the pest. However, this area must be regarded as a maximum estimate for the endangered area. On the other hand, a narrow and very conservative estimate for the endangered area can be defined based on the geographical distribution of highly susceptible host plants in Norway. This area is gardens and parks with Rhododendron spp., Viburnum spp. and F. sylvatica and areas in the wild into which Rhododendron spp. has spread and woods with F. sylvatica. Woods with F. sylvatica is limited to the county of Vestfold and some small areas in the counties of Aust-Agder and Hordaland; 5) P. ramorum is likely to have moderate economic impact on the nurseries in the PRA area with current phytosanitary measures. Without any such regulations P. ramorum is likely to have major economic impact on the nursery industry of the PRA area. The levels of uncertainties of these assessments are low; 6) With current phytosanitary measures P. ramorum is likely to have moderate economic impact on parks and private gardens in parts of the PRA area. Without any such regulations P. ramorum is likely to have major economic impact in the best climatic zones of the PRA area. The levels of uncertainties of these assessments are low; 7) The impact of P. ramorum in coniferous and mixed forests of the PRA area is likely to be minor. The level of uncertainty of this assessment is medium. The impact of P. ramorum in natural and planted deciduous broadleaf forests of the PRA area is likely to be minor due to the scattered and limited distribution of the most susceptible species. The level of uncertainty of this assessment is medium; 8) The non-commercial and environmental consequences to natural environments in the PRA area are likely to be moderate. The level of uncertainty ...

Sammendrag

A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.

Sammendrag

A survey was undertaken to investigate the occurrence of plant parasitic nematodes in the municipality of Lier located in southern Norway. A wide variety of vegetables crops are grown in this area. Soils in Lier are mostly sandy loam, and irrigation is practiced when necessary during the growing season. There is little information on the occurrence on plant parasitic nematodes in vegetables; particularly in areas where farmers have specialized in intensive production, and often grow two to three cultures of vegetables during the growing season. In the year prior to this investigation several crops had been observed with symptoms of attack by plant parasitic nematodes. The aim of this survey was to identify the species responsible for the damage. The emphasis was placed on genera of known economic importance. During the end of the growing season plants showing poor growth or symptoms of nematode damage and plants with healthy appearance were sampled. A total of 74 root samples were collected and assessed for galls and 37 soil samples were collected from the rhizospheres. In the study samples were collected from 7 producers. Five samples were taken from cauliflower (Brassica oleraceae var. botrytis), 4 from broccoli (Brassica oleraceae var. italica), 8 from pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis), 8 from lettuce (Lactuca sativa) and 1 from celery (Apium graveolens). Soil sampling included 11 samples from areas with fallow, ploughed and rotocultivated land. Root knot nematodes were not recorded in the root samples. In soil samples economically important nematode genera were recorded. Tylenchorhynchus sp. (72.9 % of samples), was the most frequently encountered genus, followed by the species Heterodera cruciferae and other Heterodera spp. (67.5 %), Pratylenchus spp. (54 %), Paratylenchus spp. (29,7 %), and Helicotylenchus spp. (8.1 %). In addition to cyst detections Heterodera juveniles were found in 32.4 % of samples. In all the samples from Pak-choy Chinese cabbage (Brassica rapa ssp. pekinensis) Heterodera cruciferae was recorded, symptoms of nematode damage was also observed in the field. The results of the survey will help in planning future research as well as in developing effective nematode management strategies suitable for vegetable producer particularly in this area. The authors are thankful to the FMLA in Buskerud County for economical support.

Sammendrag

The main Avena species that are important weeds of cereal and arable crops include A. fatua L., A. sterilis and A. barbata Pott. All three species have an abscission scar on the grains. A risk assessment of A. fatua L. as an indirect pest in Norway is given in a separate document. For both A. sterilis ssp. macrocarpa and ssp. maxima, and for A. barbata Pott, the potential for entry and establishment in Norway is considered as very low. A. sterilis ssp. ludoviciana (winter wild oats) has a moderate potential for establishment in Norway. The suitability of the environment for A. sterilis ssp. ludoviciana was therefore investigated: Our assessment of the probability of establishment indicates that the climate is not favourable for establishment of A. sterilis ssp. ludoviciana in Norway. A. sterilis ssp. ludoviciana is a problem in southern Europe and central southern England and is mainly a weed in winter cereals. While it is highly likely that the probability of establishment of A. sterilis ssp. ludoviciana has increased in Norway in recent years due to climate change and consequent changes in cultural practices, its probability of establishment in Norway is still low and it is therefore not likely that it will become a weed in Norway under current conditions. However, if the future climate of the PRA area changes, so that winter conditions become similar to conditions in southern England, while the acreage of winter cereal continues to grow, A. sterilis ssp. ludoviciana could become a weed in Norway. A. sterilis ssp. ludoviciana is not present in Denmark where winter cereals are much more widely cultivated, and the climate is more favourable than in Norway. One would therefore expect the weed to establish in Denmark before it will become a problem in Norway

Sammendrag

Planteparasittære nematoder er små rundormer som skader røttene på korn. Symptomene viser seg som tynn plantebestand, svake planter og mer ugras. I de siste årene viser henvendelser fra produsenter at problemene med nematoder er økende. Prøver med korncystenematoder, rotsårnematoder og stuntnematoder er vanlig. I prøvene hvor resistente sorter for korncystenematoder er dyrket, og skader vises, er ofte rotsårnematoder funnet. Rotsårnematoder er påvist i forbindelse med skader i alle kornarter. I en del av feltene som er undersøkt i Vestfold, Østfold, Agder, Romerike og Buskerud er det vist til dels høge populasjoner av rotsårnematoder.

Sammendrag

Planteparasittære nematoder er små rundormer som skader røttene på korn. Symptomene viser seg som tynn plantebestand, svake planter og mer ugras. I de siste årene viser henvendelser fra produsenter at problemene med nematoder er økende. Prøver med korncystenematoder, rotsårnematoder og stuntnematoder er vanlig. I prøvene hvor resistente sorter for korncystenematoder er dyrket, og skader vises, er ofte rotsårnematoder funnet. Rotsårnematoder er påvist i forbindelse med skader i alle kornarter. I en del av feltene som er undersøkt i Vestfold, Østfold, Agder, Romerike og Buskerud er det vist til dels høge populasjoner av rotsårnematoder.

Sammendrag

Bioforsk gjennomførte i samarbeid med Lier og omegn forsøksring en kartlegging av planteparasittære nematoder i Lier. Dette p.g.a. at det i 2006 ble påvist skader av nematoder i stilkselleri hos en dyrker i Lier. I vekstsesongen 2007 ble det gjort undersøkelser i 37 prøver fra grønnsakfelt fra 7 produsenter, hvor det ble dyrket blomkål, brokkoli, kinakål, isberg salat, stangselleri, og fra felter som var brakk/pløyd/frest. Det ble funnet stuntnematoder (Tylenchorhynchus sp.)i 27 prøver (72,9 %), Kålcystenematoder (Heterodera cruciferae) og cystenematoder (Heterodera spp.) i 25 prøver (67,5 %), rotsårnematoder (Pratylenchus spp.) i 20 prøver (54 %), pin-nematoder (Paratylenchus spp.)i 11 prøver (29,7 %), og spiralnematoder i 3 prøver (8,1 %).

Sammendrag

Bioforsk gjennomførte i samarbeid med Lier og omegn forsøksring en kartlegging av planteparasittære nematoder i Lier. Dette p.g.a. at det i 2006 ble påvist skader av nematoder i stilkselleri hos en dyrker i Lier. I vekstsesongen 2007 ble det gjort undersøkelser i 37 prøver fra grønnsakfelt fra 7 produsenter, hvor det ble dyrket blomkål, brokkoli, kinakål, isberg salat, stangselleri, og fra felter som var brakk/pløyd/frest. Det ble funnet stuntnematoder (Tylenchorhynchus sp.) i 27 prøver (72,9 %), Kålcystenematoder (Heterodera cruciferae) og cystenematoder (Heterodera spp.) i 25 prøver (67,5 %), rotsårnematoder (Pratylenchus spp.) i 20 prøver (54 %), pin-nematoder (Paratylenchus spp.) i 11 prøver (29,7 %), og spiralnematoder i 3 prøver (8,1 %).

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Sammendrag

Potetcystenematodene (PCN) forekommer i to arter, gul (Globodera rostochiensis) og hvit (G. pallida). Begge har fl ere raser, hvor det i Norge er påvist fi re av den gule arten. Cystene ligger i jorda og er døde hunner, mens smitten er eggene som fi nnes inne i disse. Potet er den viktigste vertsplanten. Angrepne områder får dårlig vekst og vises ofte som fl ekker i åkeren. Gul PCN er påvist på 6400 eiendommer fra Lindesnes i sør til Ørland kommune i nord. Forebyggende tiltak er viktigst for å unngå smitte. Gul PCN er en karanteneskadegjører som reguleres av Matloven. Det er meldeplikt til Mattilsynet på mistanke om infeksjon av PCN. Bioforsk Plantehelse utfører analyser av forekomst, smittenivå og rasetesting.

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Sammendrag

Potetcystenematodene (PCN) forekommer i to arter, hvit PCN (Globodera pallida) og gul (Globodera rostochiensis). Begge har fl ere raser. Cystene ligger i jorda og er døde hunner, mens smitten er eggene som fi nnes inne i disse. Potet er den viktigste vertsplanten. Angrepne områder får dårlig vekst og vises ofte som fl ekker i åkeren. Kjent utbredelse av hvit PCN er fra Grimstad i Aust-Agder i sør til Stjørdal i Trøndelag i nord. God hygiene er det viktigste tiltaket for å unngå smitte. Hvit PCN omfattes av Matloven og infi serte bruksenheter kan legges i karantene i 40 år. Det er meldeplikt til Mattilsynet ved mistanke og funn av PCN. Bioforsk Plantehelse utfører analyser og rasetesting av PCN.

Sammendrag

Commercial products sold as "Jumping beans" are seed capsules of the scrubs Sebastiana paovniana, S. palmeri or  S. bolcularis containing larvae of Cydia deshaisiana. The larva makes the capsule move when heated. The risk assessment concluded that the larvae depend on a host not present in Norway to complete its life cycle. As the host plants only grow under extreme hot, desert conditions the expected climatic changes in the foreseable future will not lead to establishment and spread of the pest.

Sammendrag

In 2007, after many years of absence, Cucumber Green Mottle Mosaic Virus (CGMMV) reoccurred in Norwegian cucumber production. The Norwegian Food Safety Authority is considering to regulate CGMMV as a quarantine pest and commissioned a Pest Risk Analysis (PRA) of the virus. The Panel of Plant Health gives the following conclusions: Both recent and previous presence of CGMMV indicate that the pest is able to establish in the PRA area. The most probable pathway for long distance spread into the PRA area is seed transmission. Infected seedlings, people, water and soil are probable pathways for short distance spread. The probability of further spread is from location to location is high. Dry heat treatment has probably been the most effective measure to prevent the spread of CGMMV. There is a moderate level of uncertainty regarding the pathway for entry of CGMMV into the PRA area. There is a low degree of uncertainty regarding the pathogen survival and possibilty for transmission, establishment and spread in Norwegian greenhouse cucumber production.

Sammendrag

Bursaphelenchus xyliphilus, the Pine Wood Nematode (PWN) is not known to occur in Norway. With the present trade pattern the probability of entry of PWN into Norway is high. The most probable pathway is wood packing material. The probability that PWN will establish and spread in Norway is high. The beetle Monochamus sutor is regarded as a potential vector, but this has not been established in nature. The currently low density may retard PWN, but it will probably not stop establishement in a longer perspective.

Sammendrag

Pine Wood Nematode (PWN, Bursaphelenchus xylophilus) is the causal organism of Pine Wilt Disease (PWD), the worst forest pest of Japan. In Europe PWN is known to exist in Portugal. The Norwegian Food Safety Authority (Mattilsynet) is concerned about the plant health risks and the consequences to the society if PWN should establish in Norway. Mattilsynet needs a scientific assessment of the proposed measures in a contingency plan for PWN. Mattilsynet also needs the risks connected with recent spread of PWN in Portugal to be evaluated before possible changes can be made in the current phytosanitary policy of Norway. On this background Mattilsynet requested a pest risk assessment of PWN from the Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM). To answer the request, VKM commissioned a draft pest risk assessment report from the Norwegian Institute for Agricultural Sciences and Environmental Research (Bioforsk). A working group appointed by VKM’s Panel on Plant Health (Panel 9) has been involved during Bioforsk’s work on the report. VKM’s Panel 9 has used the report as a basis for VKM’s opinion. The current document answers Part 1 of Mattilsynet’s request, and was adopted by Panel 9 on a meeting 3rd September 2008. VKM’s Panel 9 gives the following main conclusions of the risk assessment: The PRA area of this assessment is Norway. PWN is not known to occur in Norway. With present trade pattern the probability of entry of PWN into Norway is expected to be high. The most probable pathway for entry of PWN into Norway would be wood packaging material (WPM). The probability that PWN will establish and spread in Norway is considered as high. With regard to the so-called Pest Free Areas (PFAs) of Portugal, the criteria given in ISPM No. 4 (FAO 1995) for establishing and maintaining PFAs have not been met, and the data available is not sufficient to confirm the existence of PFAs. Acceptance of untreated conifer wood from all parts of Portugal will result in a very high probability of entry and a high probability of establishment and spread of PWN and its vector to Norway. Uncertainty factors: To the best of our knowledge PWN is absent from the PRA area. The beetle M. sutor is regarded as a potential vector or PWN, but this has so far not been demonstrated in nature. The currently low vector densities may retard establishment of the PWN and PWD, but it will probably not stop establishment in a longer perspective. Lack of information on the dynamics of PWN populations in cool climates complicates estimates of the spread of the nematode and PWD. Custom routines may fail in their detection of PWN. Import of a seemingly harmless material might therefore pose an unknown risk. WPM follows consignments of all kinds and is a good example of a hazardous material, which often escapes plant health inspections. Detailed assessments of economic consequences of a possible establishment and spread of PWN in Norway, the effects of global warming and other climate changes on the probability for PWD outbreaks, and the effect of possible phytosanitary measures, will be given in Part 2.

Sammendrag

Wild oats (A. fatua) is present in 155 out of 431 Norwegian municipalities. It is widely distributed in all municipalities in the main agricultural areas in south-east and central-east Norway, and in the municipalities close to the Trondheim fjord. Otherwise wild oats is present in only a few scattered municipalities not geographically connected to these main areas. Endangered area, not yet infested by A. fatua, is estimated to 228858 ha. This area is spread over the cereal growing part of Norway. The counties of North- and South -Trøndelag have a higher portion of endangered area not yet infested than south and central part of East Norway. The probability of entry of A. fatua from outside the PRA area (Norway) is very low. The probability of spread within Norway is high. In areas with low infestation, like in Trøndelag, the probability of spread is lower than in heavily infested areas. However, in areas with high level of infestation there are few new farms left to be infested. The official wild oats register is a valuable tool in regulations aiming to limit spread. The register also provides a tool to follow up infested farms. The register would be even more useful if inspection for infestation on new farms had been more systematic. Wild oats is no longer devastating even in cereal monocropping, due to cost efficient herbicides. However, in Norway an increasing area is infested with wild oats. The infestation may vary from only a few plants to total coverage of the field. In cereal monocropping chemical treatment with and without hand roguing is the only feasible control methods. Hand roguing alone is expensive and ineffective even on modest infestation. The structural changes in cereal farming result in more farms being managed by entrepreneurs. Field managed by entrepreneurs promotes use of herbicide even on small infestations since this is a cost effective measure to control the weed. Less official control of cereal fields can also be expected. The economical consequences are thus expected to be high. The economical consequences can be even higher in organic farming if the most profitable rotation has to be changed to a less profitable one because of wild oats infestation.

Sammendrag

El Altiplano es una de las areas mas pobladas en el mundo. Localizada a una altitud de 3500 " 4000 m, las bajas temperaturas restringe la producción de hortalizas a campo abierto. Por lo cual la major parte de hortalizas son producidas en invernaderos rústicos (carpas solares), fabricados con material local y con techos de plasticos transparente. NGOs en la region Andina han recomendado el cultivo de hortalizas para consumo y comercialización, con el proposito de incrementar y balancear la dieta alimenticia e incrementar los ingresos de los agricultores. Nemátodos fitoparásitos o el escaso manejo de estos limitan frecuentemente la producción en los invernaderos. La universidad Catolica Boliviana, tiene sus Unidades Académicas Campesinas (UAC) en el area rural dedicadas a la enseñanza practica a personas con escasos recursos, quienes, después de su formación profesional puedan contribuir al desarrollo de sus comunidades de origen. Bioforsk ha participado en el desarrollo y fortalecimiento de las bases cientificas en Nematologia de Plantas en UAC-Tiahuanaco. Agricultores en Tiahuanaco experimentaban bajos rendimientos en la producción de hortalizas. Un muestreo de nemátodos parásitos de plantas se realizo para dar apoyo a los agricultores de esta area. Muestras de suelo y plantas se recolectaron en 1999. En Todas las muestras se encontraron nemátodos parásitos de plantas. Veinticuatro muestras conteniendo suelo y plantas provienen de papa (Solanum spp.) y otros cultivos andinos. Diecisiete muestras fueron de invernaderos rústicos. Veintiun generos de nemátodos parásitos de plantas se encontraron. Los mas frecuentes fueron nemátodo del quiste de la papa Globodera rostochiensis y el nemátodo del rosario Naccobus sp. (54 %), seguidos por el nemátodo de las lesiones Pratylenchus spp., nemátodo espiral Helicotylenchus sp. Tylenchus sensu lato(41 %), nemátodo del anillo Criconemella sp. (34 %), stunt nemátodos Tylenchorhynchus spp. (29 %) y por ultimo el nemátodo agallador Meloidogyne sp. (19 %). El studio indica que nemátodos fitoparásitos tienen un efecto drastico en el rendimiento y la producción de hortalizas.

Sammendrag

El Altiplano es una de las areas mas pobladas en el mundo. Localizada a una altitud de 3500 " 4000 m, las bajas temperaturas restringe la producción de hortalizas a campo abierto. Por lo cual la major parte de hortalizas son producidas en invernaderos rústicos (carpas solares), fabricados con material local y con techos de plasticos transparente. NGOs en la region Andina han recomendado el cultivo de hortalizas para consumo y comercialización, con el proposito de incrementar y balancear la dieta alimenticia e incrementar los ingresos de los agricultores. Nemátodos fitoparásitos o el escaso manejo de estos limitan frecuentemente la producción en los invernaderos. La universidad Catolica Boliviana, tiene sus Unidades Académicas Campesinas (UAC) en el area rural dedicadas a la enseñanza practica a personas con escasos recursos, quienes, después de su formación profesional puedan contribuir al desarrollo de sus comunidades de origen. Bioforsk ha participado en el desarrollo y fortalecimiento de las bases cientificas en Nematologia de Plantas en UAC-Tiahuanaco. Agricultores en Tiahuanaco experimentaban bajos rendimientos en la producción de hortalizas. Un muestreo de nemátodos parásitos de plantas se realizo para dar apoyo a los agricultores de esta area. Muestras de suelo y plantas se recolectaron en 1999. En Todas las muestras se encontraron nemátodos parásitos de plantas. Veinticuatro muestras conteniendo suelo y plantas provienen de papa (Solanum spp.) y otros cultivos andinos. Diecisiete muestras fueron de invernaderos rústicos. Veintiun generos de nemátodos parásitos de plantas se encontraron. Los mas frecuentes fueron nemátodo del quiste de la papa Globodera rostochiensis y el nemátodo del rosario Naccobus sp. (54 %), seguidos por el nemátodo de las lesiones Pratylenchus spp., nemátodo espiral Helicotylenchus sp. Tylenchus sensu lato(41 %), nemátodo del anillo Criconemella sp. (34 %), stunt nemátodos Tylenchorhynchus spp. (29 %) y por ultimo el nemátodo agallador Meloidogyne sp. (19 %). El studio indica que nemátodos fitoparásitos tienen un efecto drastico en el rendimiento y la producción de hortalizas.

Sammendrag

Cereal cyst nematodes, Heterodera spp., are known world wide as parasites of cereals and grasses. Surveys in Norway have revealed that nematodes belonging to the H. avenae complex occur throughout the country. The cereal cyst nematode species so far recorded in Norway are H. avenae, H. filipjevi, H. pratensis, H. bifenestra and H. hordecalis. Within H. avenae the pathotypes, Ha 11 and Ha 12, "Ha- Knislinge", "Ha- Ringsåsen" and "Ha- Våxtorp" have been encountered. H. filipjevi is represented by the pathotype "West" HfW (Holgado et al., 2007). In cereals, peaks in cyst nematode populations and damage occur every 20-30 years, and seem to occur simultaneously throughout the Scandinavian Peninsula. We do not have reliable information on the mechanisms behind these wide spread fluctuations. Crop rotation and the use of cultivars with resistance are important measures for controlling cereal cyst nematodes, but require detailed information on the occurrence and density of species and pathotypes in the fields (Holgado & Andersson 2005, Holgado et al. 2005, 2006ab). In field soils Ha 11,/12, "Ha-Våxtorp" is often found together with HfW. Resistant cultivars are normally resistant to only one of two species or pathotypes in mixed field populations. Consequently the use of resistant cultivars will lead to an increase of the nematode species or pathotype capable of reproduction, which results in peaks of damage distributed in time. Failure in recognizing the time span of this dynamic may leave the farmer without access to appropriate cultivars when damage occurs. Different species and pathotypes of cyst nematodes may occur simultaneously on the same plant root (Holgado & Magnusson, 2007). This would be an unlikely event without mechanisms reducing competition. Differences in temporal, spatial and physiological niche dimensions between species would support diversity. A better knowledge of key-differences in niche parameters of cereal cyst nematode species would allow for an active management of specific populations, and stabilize their population densities at levels below the threshold of economic damage. Management of niches is management of diversity, and this would allow for an optimal selection of cultivars. In this way the unexpected peaks in cereal damage can be avoided to the benefit of a more stable and sustainable production. The dynamics and principles of coexistence of species in mixed populations need a stronger emphasis in management systems for cereal cyst nematodes.

Sammendrag

Cereal cyst nematodes, Heterodera spp., are known world wide as parasites of cereals and grasses. Surveys in Norway have revealed that nematodes belonging to the H. avenae complex occur throughout the country. The cereal cyst nematode species so far recorded in Norway are H. avenae, H. filipjevi, H. pratensis, H. bifenestra and H. hordecalis. Within H. avenae the pathotypes, Ha 11 and Ha 12, "Ha- Knislinge", "Ha- Ringsåsen" and "Ha- Våxtorp" have been encountered. H. filipjevi is represented by the pathotype "West" HfW (Holgado et al., 2007). In cereals, peaks in cyst nematode populations and damage occur every 20-30 years, and seem to occur simultaneously throughout the Scandinavian Peninsula. We do not have reliable information on the mechanisms behind these wide spread fluctuations. Crop rotation and the use of cultivars with resistance are important measures for controlling cereal cyst nematodes, but require detailed information on the occurrence and density of species and pathotypes in the fields (Holgado & Andersson 2005, Holgado et al. 2005, 2006ab). In field soils Ha 11,/12, "Ha-Våxtorp" is often found together with HfW. Resistant cultivars are normally resistant to only one of two species or pathotypes in mixed field populations. Consequently the use of resistant cultivars will lead to an increase of the nematode species or pathotype capable of reproduction, which results in peaks of damage distributed in time. Failure in recognizing the time span of this dynamic may leave the farmer without access to appropriate cultivars when damage occurs. Different species and pathotypes of cyst nematodes may occur simultaneously on the same plant root (Holgado & Magnusson, 2007). This would be an unlikely event without mechanisms reducing competition. Differences in temporal, spatial and physiological niche dimensions between species would support diversity. A better knowledge of key-differences in niche parameters of cereal cyst nematode species would allow for an active management of specific populations, and stabilize their population densities at levels below the threshold of economic damage. Management of niches is management of diversity, and this would allow for an optimal selection of cultivars. In this way the unexpected peaks in cereal damage can be avoided to the benefit of a more stable and sustainable production. The dynamics and principles of coexistence of species in mixed populations need a stronger emphasis in management systems for cereal cyst nematodes.

Sammendrag

Planteparasittære nematoder (rundormer) lever i jord og planter. Nematodene er av mikroskopisk størrelse, og noen arter fremkaller alvorlige skader på kulturplantene ved å suge på røtter og andre plantedeler. Korn kan skades alvorlig av nematodeangrep.

Sammendrag

Planteparasittære nematoder (rundormer) lever i jord og planter. Nematodene er av mikroskopisk størrelse, og noen arter fremkaller alvorlige skader på kulturplantene ved å suge på røtter og andre plantedeler. Korn kan skades alvorlig av nematodeangrep. Nyere studier viser et stort mangfold av korncystenematoder (Holgado et al., 2004). Vanlige arter og raser i Norge er H. avenae (Ha 11, Ha 12 og Ha Våxtorp) og rugcystenematoden H. filipjevi (rase Vest), mens artene H. pratensis, H. bifenestra og H. hordecalis er mindre hyppig forekommende (Holgado et al., 2007). Vi vet i dag alt for lite om de forandringer på artsnivå som ligger bak disse langsiktige populasjonsbølgene og skadene.

Sammendrag

Korncystenematoder (Heterodera spp.) er små rundormer som skader røttene på korn og andre grasarter. I korn viser symptomene seg som tynt plantebestand, svake planter og mer ugras. Skadebildet kan forveksles med surjordskade. Angrep av korncystenematoder forekommer nesten utelukkende på lette jordarter.

Sammendrag

This Pest Risk Assessment (PRA) of the fire blight bacterium Erwinia amylovora was initiated by a review or revision of a policy by the Norwegian Food Safety Authority. Fire blight was detected in Norway for the first time in 1986. The focus of infection was in and around the city of Stavanger in Rogaland county on the south west coast of the country. Mainly Cotoneaster bullatus and C. salicifolius were attacked.  The disease was contained and finally eradicated from the area in 1992. However, in 2000 fire blight re-emerged, in the same county, on the island Karmøy, separated from the first outbreak by 25 km open sea. A new containment and eradication programme was started. Nevertheless the disease continued to spread to the north, mainly due to the movement of beehives contaminated with E. amylovora, from areas with diseased plants to areas free from fire blight with warm and humid weather conditions, favorable for the development of the disease. Fire blight has been detected in private gardens, around public buildings, in recreation grounds, along roads, and in rural areas in the coastal areas of the counties of Rogaland, Hordaland and Sogn og Fjordane. It has not been detected in nurseries, in fruit-growing areas, or in other parts of the country. The main hosts are still C. bullatus and C. salicifolius and some other Cotoneaster spp. Occasionally diseased Sorbus aria, Pyrachanta and apple and pear have been detected. Recently a very limited outbreak on C. bullatus and C. salicifolius was detected in the city of Kristiansand in Vest-Agder county. The endangered area, where presence of fire blight will result in economically important loss is the commercial fruit growing areas of Norway. If E. amylovora is introduced into the main fruit growing districts, it is expected that the damage and losses to commercial fruit production and nurseries will be minor, under the current phytosanitary regime in Norway. Relaxation of the regulations in force for fighting fire blight in Norway will increase the expected damage and losses to commercial fruit production and nurseries to a moderate level. Importation of fruit trees and fruit tree propagation material from countries where fire blight is established is not expected to increase the risk of fire blight in Norway significantly, given that appropriate phytosanitary requirements and quarantine are followed.

Sammendrag

The detection in 1999 of the pine wood nematode (PWN), Bursaphelenchus xylophilus, in Portugal triggered survey activities in many European countries. With the assumption that PWN would reach frequency 10 times lower than the native B. mucronatus and the requirement of a 95 % confidence limit suggested 2 995 samples to be required for a safe statement on the absence of PWN from the territory surveyed. Samples were taken from 10 circular areas with 50 km diameter erected from a point of import of risk materials. In the period 2000-2006 3 165 wood samples, 2 880 from Pinus sylvestris, 279 from Picea abies and 6 from unknown wood, were collected from 446 logging sites, in 84 municipalities and 13 counties. Of the total material 85 % of the samples came from cutting wastes, timber or lying trees. Wood showing signs of insect activity (incl. Monochamus) formed 73 % of the total material. Nematodes were recorded in 85 % of the samples. The order Rhabditida was most frequent, followed by the orders Aphelenchida, Tylenchida and Dorylaimida. Rhabditid nematodes were equally frequent in pine and spruce, while Aphelenchida (Aphelenchus, Aphelenchoides, Cryptaphelenchus, Seinura and Bursaphelenchus) and Tylenchida (Filenchus, Lelenchus, Ditylenchus, Deladenus and Nothotylenchus) tended to be more common in pinewood. Aphelenchoides was the most common genus. The genus Bursaphelenchus occurred in 1 % of the samples. B. mucronatus was detected in 0,3 % of the samples and most often in cutting waste of pine. The pine wood nematode (PWN), B. xylophilus, was not detected in this survey. The unexpected low natural occurrence of B. mucronatus indicates that the number of potential niches for PWN also is lower than expected, and hence it will be necessary to continue this surveillance program to reach 10 000 samples. The present zone sites in central and south-eastern Norway will be supplemented with 1-2 zone sites in southwestern region of the country. In the future these zone sites will function as permanent observation areas. Care will also be taken to collect all samples from detached wood with signs of Monochamus activity.

Sammendrag

Korncystenematoder (Heterodera spp.) er et kompleks av arter og raser med forskjellige vertsplanter og skadelighet på kornsorter. I Norge er havrecystenematoden (H. avenae) rase Ha 11, H. avenae "svensk rase Våxtorp" og rugcystenematoden (H. filipjevi) "svensk rase vest" de vanligste nematodetypene. Med støtte fra Norges forskningsråd er prosjektet "Studier av arts- og rasedifferensiering innen korncystenematode-komplekset med hensikt å effektivisere tiltak mot skader i korn " gjennomført i samarbeid mellom Bioforsk, Rothamsted Research og Sveriges lantbruksuniversitet. Hovedhensikten med forskningsarbeidet var å sikre en korrekt kjennskap til nematodeart, rase og resistensforskjell mellom kornsorter, for å kunne gi riktige tilrådinger om dyrkingsopplegg og sortsvalg for den enkelte dyrker. I prosjektet har populasjoner av korncystenematoder blitt karakterisert ved bruk av morfologi, biotester og molekylære metoder. Resultatene har dannet et grunnlag for en effektiv bekjempelse, og en inntektsøkning for kornprodusenter. I dag benytter flere produsenter resultatene i praksis.

Sammendrag

Hvit potetcystenematode (Globodera pallida) som ble oppdaget på senhøsten 2004 og tidlig i 2005 i Stjørdal er det hittil største kjente infeksjonsarealet i Norge for denne nematodearten. Påvisningen resulterte i at ca. 1000 dekar fordelt på 6 eiendommer er lagt i 40 år karantene med forbud mot dyrking av potet og bortføring av jord. Med bakgrunn i nasjonal og internasjonal vitenskaplig kunnskap om hvit PCN er det ikke uten grunn at denne nematoden er klassifisert som karanteneskadegjører. Den er en direkte trussel mot hele Norges potetproduksjon, og en videre spredning til nye dyrkingsområder vil være meget uheldig både for potetnæringen og landbruksnæringen i sin helhet.

Sammendrag

Det finnes flere nematode-arter som angriper korn. Biotester mot vanlige arter og patotyper av korncystenematoder ble gjennomført i 2005 og 2004 (Holgado & Andersson, 2005). Resultatene viser til dels at flertallet kornsorter ikke er resistente mot alle forkommende arter og patotyper, til dels at det finnes ulike grader av resistens i våre kornsorter. Bekjempelse av korncystenematoder med bruk av resistente kornsorter krever derfor kjennskap til hvilke arter og patotyper som forekommer i de enkelte feltene.

Sammendrag

Cereal cyst nematodes, Heterodera spp., are recognised throughout the world as economically important parasites of cereals. The virulence status on cereal cultivars differs between and within different species of the H. avenae-complex, and several pathotypes occur among them. A survey during 1995-2005 in Norway revealed that Heterodera spp. is common throughout the country. Studies in Norway have recorded H. filipjevi and also additional and possibly new species. A number of cereal cyst nematode populations from various regions of Norway, Sweden and the British Isles have been analysed using molecular, morphological and host range studies during the last three years. Fifteen populations, of the initial group of forty, are being studied more closely. Studies using isoelectric focusing and silver staining have detected divergent populations of H. avenae. The Swedish populations Ringsåsen seemed to be identical to a population found in Australia and the Swedish population Halland shows a protein profile separate from H. avenae. DNA studies are being used to determine if these populations are new species. An assortment of cereal cultivars, based on an international collection used for resistance testing, differentiates three groups, H. avenae (pathotypes Ha 11 and Ha 12), H. filipjevi (pathotype "West"), and a population from central Norway close to H. pratensis. Knowledge of the diversity of cereal cyst nematodes and their multiplication rates on their cereal hosts is of fundamental importance for efficient control strategies involving resistant cultivars. In Norway, management based on these parameters are in operation and have increased yields and profits to cereal farmers.

Sammendrag

The pine wood nematode, Bursaphelenchus xylophilus, which is indigenous to North America, was introduced to Asia in the early 1900 and now causes severe damage to susceptible pine species in Japan, China, Korea and Taiwan. B. xylophilus was included in the A1 list of quarantine organisms by EPPO (European Plant Protection Organization) in 1985. B. xylophilus was reported for the first time in Europe in Portugal in 1999. There are more than 50 described species within the genus Bursaphelenchus worldwide, that are associated with coniferous and deciduous trees and spread by insect vectors. Within this genus is a group of morphologically very similar species; B. xylophilus, B. mucronatus, B. fraudulentus, B. kolymensis, B. conicaudatus and B. luxuriosae. This group of species is often referred to as the "B. xylophilus group". Due to the morphological similarity of the species, identification of Bursaphelenchus species in the B. xylophilus group is difficult. The common method of molecular identification for separating species within the B. xylophilus group is the use of ITS-RFLP (Hoyer et al. 1998). We have developed a multiplex polymerase chain reaction (PCR) method with specific primers, and the primers amplified product were 740, 340 and 300 bp for B. xylophilus, B. fraudulentus and B. mucronatus respectively. No cross reactions on the three studied species were observed. In contrast to the previously described PCR-RFLP method, this new method allows detection not only on pure isolates, but also on crude nematode suspensions from wood samples, and it could be very useful for quarantine purposes. References Hoyer U, Burgermeister W, Braasch H 1998 Identification of Bursaphelenchus species (Nematoda, Aphelenchoididae) on the basis of amplified ribosomal DNA (ITS-RFLP). Nachrichtenbl. Deut. Pflanzenschutzd. 50:273-27. Mota M M, Braasch H, Bravo M A, Penas A C, Burgermeister W, Metge K, and Sousa E 1999. First report of Bursaphelenchus xylophilus in Portugal and in Europe. Nematology 1:727-734. Smith, I. M. 1985. Pests and disease problems in European forests. FAO Plant Prot. Bull. 33:159-164. Yi C, Park J, and Chang K 1989. Occurrence of pinewood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and its vector, Monochamus alternatus Hope, in Korea. Pages 183-193 in: Proc. IUFRO Reg. Workshop For. Insect Pests and Tree Dis. in NE Asia. For. Prod. Res. Inst., Tsukuba, Japan.

Sammendrag

Effects of composting on survival and reproduction of the potato cyst nematode (PCN) Globodera rostochiensis were investigated in 150-liter pilot scale reactors. Small bags containing cysts of PCN were incubated in organic waste and composted for 8, 15 or 29 days. Temperatures in the areas close to the cyst bags were monitored. Survival, measured by hatching, was reduced by 99.9% already after 8 days of composting and at 29 days no hatching was recorded. A few eggs, however, still hatched after being composted for 15 days and exposed to temperatures higher than 60°C for several days. Maximal temperatures and thermal exposure time as such could not explain the hatching pattern of PCN, so other factors are likely to be involved in causing lethality. PCN failed to reproduce after 8 days of composting with temperatures reaching a minimum of 50°C during the period. Hence, eight days of composting where all material have reached a temperature of minimum 50°C during the period, could be regarded as a satisfactory method for sanitation of PCN.

Sammendrag

Nå er furubukkarten Monochamus alternatus funnet innført til Norge i emballasjematerialet. Arten er den viktigste overføreren for den svært farlige furuvednematoden som drreper furutrær i Sørøst-Asia og Portugal.

Sammendrag

Cereal cyst nematodes, Heterodera spp. are known world-wide as parasites of cereals and grasses. Surveys of cereals in Norway have revealed that nematodes belonging to the H. avenae complex occur throughout the country, and that H. avenae (oat cyst nematode) is the most common species followed by H. filipjevi (rye cyst nematode). H. avenae and H. filipjevi are of economic importance in Scandinavia. H. avenae has two common pathotypes, Ha 11 and Ha 12. Work in Sweden, however, has detected the three additional pathotypes H. avenae- Knislinge, H. avenae- Ringsåsen and H. avenae- Våxtorp. These pathotypes were detected also in the Norwegian surveys. In Sweden H. filipjevi has two pathotypes, "East" and "West". In Norway, only the pathotype "West" has been detected so far. Nematode management practices must be based on the knowledge of the population dynamics, the population density required to cause economic damage, and the measures capable of reducing or keeping the population density below the threshold for economic damage. Crop rotation and the use of cultivars with resistance are important measures for controlling cereal cyst nematodes. For several years it has been known that resistance to cereal cyst nematodes may be found in some commercial cultivars, although no conscious breeding for resistance has been attempted. In 2004 and 2005 a majority of cereal cultivars on the Norwegian market were tested for susceptibility/resistance towards H. avenae pathotype Ha 11, H. avenae pathotype "Våxtorp" and H. filipjevi pathotype "West" The test program included 30 cultivars of barley, 23 cultivars of oats and 6 cultivars of summer wheat. The objective of this work was to increase our knowledge on cultivar selection for farmers. Resistance against Ha11 was found in 5 barley, 3 oat cultivars and in 1 wheat cultivar. Resistance against H. avenae pathotype "Våxtorp" was not present in barley, but 4 oat cultivars, and 1 wheat cultivar were resistant. For H. filipjevi "West" resistance was not detected in wheat, but in 6 barley and 13 oat cultivars. In Norway management systems based on careful nematode identification and good knowledge on appropriate resistant cultivars are in operation. Resistant barley is generally recommended when nematode populations are high due to its high tolerance compared to resistant oats. Farmers implementing this program have reported increased cereal yields on the average of 1000 kg /ha. It has been calculated that by implementing this program in full the county of Vestfold could make an economic gain of 800 000 " annually.

Sammendrag

Cereal cyst nematodes, Heterodera spp., are known worldwide as parasites of cereals and grasses. Surveys of cereal fields in Norway have revealed that nematodes belonging to the H. avenae complex occur throughout the country, and that H. avenae (the oat cyst nematode) is the most common species, followed by H. filipjevi (the rye cyst nematode). Both species are of economic importance in Scandinavia. H. avenae has been found in two common pathotypes, Ha 11 and Ha 12. Work in Sweden, however, has detected three additional pathotypes, H. avenae "Knislinge", H. avenae "Ringsåsen" and H. avenae "Våxtorp". These pathotypes were found also in the Norwegian surveys. In Sweden H. filipjevi has two pathotypes, "East" and "West". In Norway, only pathotype "West" has been detected so far. Nematode management practices must be based on the knowledge of the relationship between initial nematode density and yield, the population dynamics, and the measures capable of reducing or keeping the population density below the threshold for economic damage. Crop rotation and the use of cultivars with resistance are important measures for controlling cereal cyst nematodes. Several cereal cultivars with resistance to H. avenae are on the market. As to H. filipjevi, resistance may be found in some commercial cultivars, although no intentional breeding for resistance against this nematode species has been attempted. In 2004 and 2005 the majority of the cereal cultivars on the Norwegian market were tested for susceptibility/resistance towards H. avenae pathotype Ha 11, H. avenae pathotype "Våxtorp" and H. filipjevi pathotype "West". Management systems, based on careful nematode identification and good knowledge of appropriate resistant cultivars, are in operation in Norway. Resistant barley is generally recommended when nematode populations are high due to its high tolerance compared to resistant oats. Farmers implementing this program have reported increased cereal yields on the average of 1000 kg /ha. It has been calculated that by implementing this program in full the county of Vestfold could make an economic gain of 800 000 " annually.

Sammendrag

Korncystenematoder (Heterodera spp.) er et kompleks av arter og patotyper. Så langt er det i Norge påvist den vanlige havrecystenematoden (Heterodera avenae) patotype Ha 11, H. avenae svensk patotype ”Våxtorp” og rugcystenematoden (H. filipjevi) svensk patotype ”Vest”. Biotest med disse patotypene ble gjennomført i 2004 og 2005 ved Sveriges Lantbruksuniversitet i Alnarp. Tester i veksthus av 63 kornsorter viste at de fleste sortene i testen var mottakelige for Ha 11 og Ha Våxtorp. Dette var også tilfelle i tester med H. filipjevi Vest for sorter av bygg og vårhvete, mens et flertall av havresortene var mer eller mindre resistente. Resultatene viser også at det finnes flere sorter på det norske markedet som kan benyttes for å holde korncystenematodene på et lavt nivå. I bygg var Frisko, Helium Meltan, Otira og Simba resistente mot Ha 11. For Ha Våxtorp viste ingen av de testede sortene seg å være resistente. Byggsortene Antaria, Frisko, Gunilla, Iver, Pernilla og Sunnita var resistente mot H. filipjevi Vest. I havre viste sortene Sanna, Gunhild og Vital resistens mot Ha 11, og mot Ha Våxtorp var sortene Gunhild, NK98059, Sanna og Vital resistente. Mot H. filipjevi Vest var Bikini, Bessin, Gunhild, Kerstin, Liberto, Matilda, NK 98008, NK980591, Olram, Pol, Sanna, SW 98195 og Vital resistente.

Sammendrag

Furuvednematode (Bursaphelenchus xylophilus) er en karanteneskadegjører som kan angripe og forårsake enorme ødeleggelser i furuskog. Nematoden er til nå ikke påvist i Norge.

Sammendrag

Soil nematodes are important components of soil ecosystems, but have so far received little attention in organic farming. Many free-living nematodes are important for decomposition and mineralization processes, and it is estimated that the nematode grassing of bacteria would mobilise up to 124 kg N ha-1yr "1. Furthermore, their feeding activities on the rhizoplane may reduce microbiological immobilisation of nitrogen. In organic farming the use of clover and other nitrogen fixating legumes is important for securing appropriate nitrogen levels. Clover is an excellent host for a wide range of plant parasitic nematodes. In organic farming damage has so far been reported for root lesion nematodes (Pratylenchus spp,), clover cyst nematode (Heterodera trifolii) and the northern root knot nematode (Meloidogyne hapla). Nematode monitoring is a prerequisite for management. Effective control measures of plant parasitic nematodes and good management systems for beneficial nematodes would allow for increasing yields and improved quality. Organic farming puts new challenges to the science of nematology, and would profit from a close interaction between nematology and soil science.

Sammendrag

A survey of cereals, carried out in 1995-2005 in Norway, revealed that Heterodera spp. are common throughout the country. Nematodes belonging to the H. avenae complex were recorded from the county of Agder in southern Norway (58.08o N) to the county of Nordland in the north (65.5o N), and this so far is the most northern location reported for Heterodera in cereals. Studies in Norway have recently recorded H. filipjevi and also additional and possibly new species. H. filipjevi is of economic importance in Scandinavia. It was first recorded in the beginning of the 1970s and then referred to as the "Gotland strain of H. avenae". Biotests carried out in Sweden demonstrated the occurrence of two pathotypes, "East" and "West", named according to their geographical distribution. In Norway H. filipjevi, was first recorded causing damage to winter rye, Compared to H. avenae, H. filipjevi has the ability of hatching easily and at low temperatures, this ability of rapid hatch suggests that field population densities could easily be underestimated if based on cyst extractions only. Hence, accurate assessments of pre-plant densities of H. filipjevi require quantification of infective juveniles in soil. Nematode management practices must be based on the knowledge of the population dynamics and the threshold levels needed to cause economic damage. Tests of 63 cereal cultivars on the Norwegian market revealed 13 oat and six barley cultivars to be resistant to H. filipjevi "West" It is important that resistant cultivars of barley are recommended when nematode populations are high, as resistant barley is more tolerant than resistant oats. However even in rotations with resistant barley the farmer should be prepared to accept some yield losses in the first year of management. One important challenge in the management of H. filipjevi is the common occurrence of mixed populations. H. avenae "sensu stricto" and/or its slightly diverging form "Våxtorp" is often found together with H. filipjevi. From our experience the dynamics of mixed populations needs a stronger emphasis in management systems for cereal cyst nematodes. Our knowledge of the occurrence and distribution of cereal cyst nematode species and pathotypes in Norway has increased, and the screening of cultivars for resistance against various populations particularly H. filipjevi, H. avenae "sensu stricto" and the "Våxtorp"-type has been intensified. Hence, today farmers can be provided with control strategies which are easily implemented. With this management system, farmers in the county of Vestfold have increased cereal yields. After 3-4 years of implementation farmers have reported yield increases averaging 1000 kg ha. Compared to the earlier situation (when control was not practiced), a full implementation of the current management program in the county of Vestfold has been estimated to give an annual economic gain in the order of "800 000.

Sammendrag

Nålnematoden Longidorus elongatus er allment forekommende i Norge og mange kulturvekster er gode vertsplanter. Nematoden er virusvektor, men er også en viktig primær skadegjører i jordbær. Nematodeangrepet gir dårlig vekst og plantedekning, redusert avling og mindre antall utløpere. Angrepne rotspisser blir kølleformet. Skadeterskelen er 3-5 individer per 250 gram jord, og det regnes med et avlingstap på 50% ved en nematodetetthet på 100 individer. Nematodetall på 600 individer per 250 gram jord gir totalskade i jordbær. Andre kulturplanter som skades er kepaløk, purre, knollselleri, rødbeter, raigras, solbær og rips. Nålenematoden er en regulert skadegjører og i utgangspunktet skal jord for produksjon av sertifiserte jordbærplanter være fri for L. elongatus, men stiklingsproduksjon av sertifiserte planter på plastduk er tillatt ved lave nematodetettheter. Et viktig forebyggende tiltak mot nålnematoder, i tillegg til bruk av sertifisert plantemateriale, er jordprøvetaking for nematoder før nye jordbærfelt etableres. For å redusere skader av nålnematoder på infiserte arealer er det viktig å brakklegge eller å bruke ikke-vertsplanter som bringebær, erter, havre, rabarbra, hvitkål og rug i vekstskiftene. Flere ugras er vertsplanter og ugraskontroll er derfor en viktig faktor som må vektlegges.

Sammendrag

Protein variability of 27 populations of cyst nematodes belonging to the Heterodera avenae complex were studied using isoelectric focusing (IEF). Sixteen Norwegian populations were compared with standard populations of H. avenae, H. filipjevi, H. mani and H. arenaria. Norwegian populations were also tested for pathotype on selected cereal cultivars. Based on differences in the protein banding pattern, eight clusters of populations could be recognised. Nine Norwegian populations grouped together with H. avenae standards. The three Swedish populations: Knislinge, Ringsåsen and Våxtorp, previously classified as H. avenae, differed from this species, from H. filipjevi and from each other. Four Norwegian populations clustered together with the Våxtorp population. Two Norwegian populations formed a cluster together with a Swedish H. filipjevi standard. The Norwegian population Brekstad differed from all other populations, as did the standards of H. mani and H. arenaria. Pathotype testing of the Norwegian populations identified ten populations as H. avenae pathotype Ha 11, while three were close to pathotype Ha 12. The two H. filipjevi populations were close to the Swedish pathotype west. The Brekstad population differed from all others also in host spectrum. This population and the Våxtorp-group demonstrate a complexity within the Norwegian cereal cyst nematodes that merits further investigation.

Sammendrag

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".

Sammendrag

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.

Sammendrag

Rotgallnematoder (Meloidogyne spp.) er globalt de mest skadelig nematodene og forårsaker mer en 10% avlingsreduksjonen på verdensbasis. M. arenaria, M. javanica, M. incognita, og M. hapla er de viktigste artene. Totalt er det beskrevet mer enn 90 arter av rotgallnematoder, og av disse er ca. 20 så langt blitt funnet i Europa. På det Europeiske kontinent er M. hapla mest utbredt, mens M. chitwoodi og M. fallax er påvist i begrensede områder. De to sist nevnte artene er karanteneskadegjørere i EU og tiltak iverksettes for å hindre videre spredning. M. chitwoodi and M. fallax betraktes som en trussel for Europa og begge artene forårsaker alvorlige kvalitetsskader på potet og grønnsaker som gulrot. M. chitwoodi og M. fallax er ikke påvist i Norge. Risikoanalysestudier med hensyn til M. chitwoodi og M. fallax, har vist at begge artene kan forventes å kunne etablere seg i Norge, og at en generasjon kan forekomme i Midt-Norge og to generasjoner i Sør-Norge. Utvikling av skade på potetknoller vil være mulig i Sør-Norge.

Sammendrag

In this survey of 2002, 600 samples were collected from 83 forest blocks in the counties Akershus, Buskerud, Oppland and Østfold. The sampling activity involved 16 municipallities situated mainly within the three zone sites A, B, and C. Samples from Scots pine (Pinus sylvestris) formed 89%, while samples of Norway spruce (Picea abies) made up 10% of the total sample volume. Timber and forest debris were the most common objects sampled. Sixty-five percent of the pine samples and 81% of the spruce samples showed signs of Monochamus activity. Nematodes were common and occurred in 94% of the samples analysed. Thirteen samples of pinewood were positive for the genus Bursaphelenchus. Bursaphelenchus mucronatus was recorded for the third time in Norway, and was detected in forest debris attacked by Monochamus at Bjørdalen in the municipality of Eidsberg in the county of Østfold. The pine wood nematode Bursaphelenchus xylophilus was not detected in this survey.

Sammendrag

In this survey of 2003, 600 samples were collected from 96 forest blocks in the counties of Aust-Agder and Vest-Agder in southern Norway. The sampling activity involved 19 municipalities situated mainly within the two zone sites D and E close to Kristiansand and Arendal. Samples from Scots pine (Pinus sylvestris) formed 92%, while samples of Norway spruce (Picea abies) made up 8% of the total sample volume. Timber and forest debris was the most common objects sampled. Ninety-eight percent of the samples, regardless of tree species, showed signs of Monochamus activity. Nematodes were common and occurred in 90% of the samples analysed. Eight samples of pinewood were positive for the genus Bursaphelenchus. This genus did not occur in spruce. Bursaphelenchus mucronatus was detected in 6 samples of forest debris of pine attacked by Monochamus and collected in the county of Aust-Agder. In the municipality of Evje and Hornes B. mucronatus was detected at Skjerkelia and Sutestad. In the municipality of Froland the nematode was found in two samples from Budalsfjellet, and in one sample from Mjålandsvatn. In the municipality of Birkenes one sample from Vågsdalen contained B. mucronatus. This is the fourth report on the occurrence of B. mucronatus in Norway. The pine wood nematode Bursaphelenchus xylophilus was not detected.

Sammendrag

Rotsårnematoden Pratylenchus penetrans er vanlig som parasitt på en rekke kulturplanter og kan blant annet forårsake stor skade i beplantninger med eple og kirsebær. Andre viktige nematodetyper på frukttrær er "pin-nematoder" (slekten Paratylenchus), ringnematoder (familien Criconematidae), spiralnematoder (familien Hoplolaimidae), dolknematoder (Xiphinema) og nålnematoder (Longidorus). Svært viktig for skade på trærnes utvikling og fremtidig produksjonsevne er antallet nematoder i jorda, særlig det første året etter planting. Forståelse av nematodenes effekter på frukttrær krever kjennskap til de enkelte artenes oppformeringsevne på den aktuelle grunnstammen og skadelighet på både grunnstammer og sort. Artikkelen viser også undersøkelser som er gjort i et 11 år gammelt morellfelt ved Ullensvang forskningssenter i Hardanger. Grunnstammene i bestandet var GM61, GM69, Colt og Prunus avium "Sandøya", fordelt på sortene Van, Kristin og Stella. Strategier for å unngå/redusere skade av nematoder kan være; ta jordprøver for å kartlegge nematodesituasjonen før planting, bruk av nematodefrie grunnstammer, bruk av planter som er tolerant eller resistent mot nematoder, og valg av underkulturer som ikke medfører sterk oppformering av nematoder.

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Sammendrag

Frukttrær er en langsiktig kultur, hvor angrep av planteparasittære nematoder kan føre til avlingstap og tredød. Nematodenes effekter på frukttrær beror av nematodeartenes oppformeringsevne og skadelighet på det aktuelle plantematerialet. Forekomst av nematoder og skuddtilvekst i en beplanting av moreller ved Ullensvang forskningssenter i Hardanger indikerte en viktig rolle for nematoder i vekstforstyrrelser. For å begrense nematodeskadene i frukthager må jordprøver tas ut senest året før planting. Ved høye nematodetettheter bør feltet brakkes eller tilsåes med underkultur som vil senke smittenivået før det plantes med nematodefritt plantemateriale.

Sammendrag

The soil conditioner, VEAS-Biosolids, is producted through filter pressing, heating and vacuum drying of digested 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 filter press and thermal vaccum dryer. Germ carriers with nematode cysts and seeds of wild oat, were placed in the process vessel and also out-side as controls. The process had a 100% efficacy in sanitation of PCN and wild oat. The pre-exposure to sludge reduced viality and viability in the controls. A more complete paper with VEAS-concept is found on VEAS homepage www.veas.nu.

Sammendrag

Several species of cyst nematodes in the genus Heterodera attack cereals. The most common, and maybe the most important species, is the cereal cyst nematode (CCN) H. avenae, which was first reported in Norway in 1925. The dominant cereal in Norway is barley, followed by oats and wheat. The acreage grown under wheat has increased by 70% during 1985 to1995. Field damage by cereal cyst nematode is shown as patches with uneven growth, which is most clearly seen in oats; in addition to cereals several species of grass are hosts of some cereal cyst nematodes. This report gives a background to some problems related to cyst nematodes on cereals, and is the result of a recent survey of the genus Heterodera in cereals in Norway. The results are based on the analysis of 220 samples for the years 1995-1998. Nematodes in the genus Heterodera are common in Norwegian cereal fields and have been recorded from the county of Agder in the county of Nordland. In this survey the highest frequencies of occurrence were found in oats and wheat. Earlier studies have demonstrated Ha51 to be the dominant pathotype of H. avenae in Norway. The observed increase in damage may relate to the lack of resistance of Ha51 in current cultivars, and a shift in pathotype frequency of CCN. The increased acreage of wheat and the cultivation of susceptible cereals when used as a pre-crop to oats and wheat could also contribute to the increase in damage. Knowledge of the occurrence and distribution of different species and pathotypes of cyst nematodes on cereals in Norway also needs to be developed. Screening the current cultivars for resistance against cereal cyst nematodes, and finding effective nematode pest control strategies is also urgently needed.

Sammendrag

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

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.

Sammendrag

In 2001, a zone site C, was established as a circular areas with 50 km radius and centred in Greåker close to Sarpsborg in South-eastern Norway. Zone site C is complementary to the similar zone sites A and B established in 2000. From June 2001 to December 2002, 601 wood samples were collected from 66 forest blocks, all situated within the 3 existing zone sites A, B and C. The sampling was carried out in the provinces Akershus, Buskerud, Vestfold and Østfold, but was concentrated to the South-eastern region, where 399 samples were taken from 45 forest blocks in the province of Østfold. Samples from Scots pine (Pinus sylvestris) formed 96% of the collected material, while Norway spruce (Picea abies) was a minor fraction. Lying trees and various kinds of detached wood formed the main part of the objects sampled. The frequency of objects showing signs of attack by wood boring insects was 44%. Some samples were also taken in Porsgrunn in the province of Telemark from a consignment of spruce imported from Russia. Nematodes were often more common in samples from objects with signs of insect activity. In four samples, all from lying pine trees, nematodes belonging to the genus Bursaphelenchus were detected. Bursaphelenchus mucronatus was recorded for the second time in Norway, and occurred in a lying pine tree attacked by Monochamus at Ombudstvedt in the municipality of Våler in the province of Østfold. The pine wood nematode Bursaphelenchus xylophilus was not detected, nor in forests or in 5 samples from spruce imported from Russia

Sammendrag

Det har dei siste åra vore auka satsing på produksjon av klyppegrønt og juletre her til lands. Etter kvart har det dukka opp ein del problem med sjukdomar og skadedyr. Lawsonsypress (Chamaecyparis lawsoniana), krussypress (C. pisifera "Squarrosa") og kristtorn (Ilex aquifolium) er store klyppegrøntkulturar. Desse klyppegrøntkulturane og juletre er utsette for sjukdom. Dette er bakgrunnen for at kartleggingsprosjektet vart sett i gang. Kartlegginga tok til i april i 2000. Nokre prøvar vart òg tekne ut ved ei synfaring i klyppegrøntfelt i Nord Rogaland og Sunnhordland i november 1999. Totalt vart 19 klyppegrøntfelt vitja. Det vart tatt ut både plante- og jordprøvar. I tillegg til planteprøvane som vart tatt ut ved synfaringane, vart det også sendt inn mange prøvar. I alt vart 189 planteprøvar undersøkte for sopp og andre skadegjerarar, medan 14 jordprøvar vart undersøkte for nematodar. På lawsonsypress var det to dominerande skadebilete. Det eine var at baret vert blast og seinare brunt. På slike prøvar vart det funne Phytophthora spp. Desse algesoppane førte ofte til at plantene gjekk heilt ut på grunn av at rotsystemet var øydelagt. Skadeomfanget vart mellom anna i eit felt i Rogaland vurdert til 51 % daude eller skadde planter. Det andre skadebiletet på lawsonsypress var klorose og seinare nekrose i fjorårsveksten. Her viste analysar av bar magnesiummangel. Ved sterk mangel vart også årsveksten ramma. På krussypress fann ein òg ofte bar som vart gråleg og seinare brunt. I dette materialet vart det mellom anna funne einerkvistdød (Phomopsis juniperovora). Frå mellom anna USA, er det kjent at denne soppen kan føra til at planter vert sterkt skada og til og med daudar. I felt som har vore med i dette kartleggingsprosjektet, har ein sett at 100 % av krussypressplantene er meir eller mindre skadde av einerkvistdød. Det vart funne mange ulike soppar på prøvane. Dei aller fleste av desse vert ikkje rekna som patogene, men nokre av dei kan gjera skade dersom vekstane er svekte av frost, nematodar eller anna. I jordprøvane frå klyppegrøntfelta vart det funne til dels høg tettleik av nematodar. Dei fleste slektene som vart funne vert rekna som skadelege for planter, enten direkte eller i interaksjon med til dømes sopp og bakteriar.

Sammendrag

Potetcystenematodene (PCN) Globodera spp. er opprinnelig fra fjelltrakter i Peru og Bolivia. PCN er en av de mest avanserte og fremgangsrike planteparasitter. PCN ble påvist i Europa av Kühn i 1881, og i 1923 erklærer Wollenweber den som egen art. Stone i 1973 skiller PCN i to arter. Gul PCN (Globodera rostochiensis) og hvit PCN (G. pallida). I Norge ble PCN først påvist 1955 i Agderfylkene. PCN har spredt seg raskt og i1993 ble de første funn gjort i Nord-Trøndelag. På verdensbasis er PCN funnet utbredt i 23 land og har en begrenset forekomst i 42 land, og i tillegg er det 130 land det ikke er blitt påvist enda. Både gul og hvit PCN er klassifisert som karanteneskadegjørere i 106 respektive 55 land. I de siste årene har PCN blitt påvist i Australia, Canada og USA, som på nytt satt fokus på hvor lett PCN kan spres og hvilke nasjonale konsekvenser PCN har. De plantesanitære og økonomiske konsekvensene av PCN er betydende. I EU vil PCN bli regulert i det nye EU direktivet 2007/33/EC som implementeres nå. Formålet med direktivet er å begrense og kontrollere spredningen til PCN. I direktivet gjøres det ingen forskjell mellom gul og hvit PCN, det nevnes at arealer for settepotet og planter til videre dyrking må ha en offisiell dokumentasjon om PCN status, det skal årlig gjennomføres offisiell prøvetaking av 0,5 % av arealet av felt for produksjon av annen potet enn settepotet. Smittede felt får ikke brukes til produksjon av settepotet eller planter til videre dyrking. Bekjempelsestiltak iverksettes på smittede felt som skal brukes til produksjon av annen potet enn settepotet. Ved resistensbryting skal PCN populasjonen rase testes. Det skal sendes en årsrapport til EU om tiltak som iverksettes i hvert land. I dag benyttes nematicider for å kontrollere PCN, og samtidig disponeres mye resurser for å foredle sorter med resistens. Potetprodusenter i England bruker ca. Nok. 584 mill. pr år for å sikre sin potetproduksjon. Etter siste oppdagelse av PCN i Australia har mye ressurser blitt benyttet for å utrydde PCN, da det er blitt estimert at det vi koste ca. Nok 216 milliarder i en periode av 20 år hvis PCN blir utbredt i landet. I tillegg til Australia har land som Israel, USA og Canada investert store ressurser for å utrydde PCN, da de mener at på lang sikt er dette billigere enn å leve med PCN. For å gjøre dette mulig har disse land satt i verk strenge restriksjoner. Disse restriksjonene omfatter forbud mot å dyrke potet og andre vertsplanter, benytte store menger nematicider, og prøvetaking. I USA har det 2006-2009 blitt analysert 257 700 prøver, etter påvising av hvit PCN i 9 felt i Idaho. USA har som målsetting å utrydde PCN på 7 år. Som resultat av EU:s direktiv (EC) No 1107/2009 om begrensning av giftige kjemikaler som forårsaker som forårsaker helse- og miljøproblem forventes bruket av de fleste nematicidene å være forbudt i 2015. For å imøtekomme disse utfordringene har forskere i Storbritannia startet sekvensering av hvit PCN. Det er ledet av University of Leeds, i samarbeid med Rothamsted Research, SCRI, og Sangers Institute, og har et budsjett av Nok 15 mill. Det forventes at dette kan gi nye bærekraftige alternativer til bekjempelse av PCN. I tillegg bruker andre Europeiske land ressurser på å finne alternativer for bekjempelse med fangevekster og biofumiganter. I det fleste land omfatter bekjempelse i dag bruk av nematicider, bruk av sertifisert settepotet, og kontrollert bruk av resistente sorter for å unngå oppformering av resistensnedbrytende raser. I tillegg har de et karanteneregelverk. Dette bidrar til en lønnsom potetproduksjon.

Sammendrag

Two zone sites, i.e. two circular areas with 50 km radius, were established in southern Norway. The zone sites were centred in Tofte (the location of a major pulp mill) and in Drammen (the site of a major timber yard). From June to October 2000, 66 forest blocks were visited, 65 of which were situated within the zone site areas. Samples were collected from 40 forest blocks, especially from wood attacked by wood boring insects. At 34 forest blocks, trees of Scots pine, Pinus sylvestris, or Norway spruce Picea abies were provided as trap-logs for Monochamus spp. This material will be sampled in the survey of 2001. Some samples were also taken from a wood chip pile and from imported wood material. The total number of wood samples analysed for nematodes were 275. Out of these, 214 samples were collected from forest trees, stumps, timber and logging wastes of P. sylvestris and P. abies. Three samples contained nematodes belonging to the genus Bursaphelenchus, but the Pine Wood Nematode (PWN), B. xylophilus, was not detected. Similarly, this nematode was not detected in the 10 samples of wood chips, or in the 25 samples of imported lumber or in the 26 samples of imported solid wood packing material. In order reach the minimal number of 3000 samples within reasonable time, the number of samples for the next survey season of 2001 needs to be increased drastically. To achieve this, the sampling will continue within the existing zone sites, and be extended into new zone sites to be established in 2001.

Sammendrag

Eit dyrkingsproblem er at søtkirsebær-trea utan synlege sjukdomsteikn brått kan stagnera i vekst og døy endå om feltet har fått optimalt stell. For tida er det ingen konkrete rådgjerder for dyrkarane bortsett frå å planta nye tre i staden for dei som gjekk ut. Med finansiering frå Statens Landbruksbank har Planteforsk Ullensvang i samarbeid med Planteforsk Plantevernet gjennomført det eitt-årige prosjektet "Kartlegging av årsaker til tredaude i søtkirsebær" i 1999. Kartleggingsarbeidet var delt i to: 1.Kartlegging av 5 bruk som har problem med tredaude blant medlemene til Hardanger Frukt og Bær med utttak og analyse av nematode-, sopp-, virus- og jord- og bladprøvar saman med feltinspeksjonar. 2. Spørjeundersøking til søtkirsebærdyrkarar ved 5 fruktlager i Ullensvang om tilhøve som kan tenkjast å påverka tredaude i søtkirsebær . Grupper av rotnematodar som gjer skade på frukttrea var registrert i alle hagane og kan såleis vera medverkande til symptoma. Det var også mogeleg å relatera høge populajonar av rotsårnematodar til dårleg tilvekst og høge spiralnematodetal til tidlegare observasjonar av tredaude. Det vart ikkje påvist at ulike insekt, soppar, bakteriar eller virus var primærårsak til denne tredauden. Spørjeundersøkinga viste at mange søtkirsebærdyrkarar meinte det var skilnad mellom kor utsette ulike sortar og grunnstammer var for tredauding i frukthagane. Gjenplanting på same arealet kort tid etter at det var rydda steinfruktplanting fremja tredauding. Lauvtrebarkbillen var årsak til tredaude, men då er diagnosen oftast enkel å stilla.

Sammendrag

Eit dyrkingsproblem er at søtkirsebær-trea utan synlege sjukdomsteikn brått kan stagnera i vekst og døy endå om feltet har fått optimalt stell. For tida er det ingen konkrete rådgjerder for dyrkarane bortsett frå å planta nye tre i staden for dei som gjekk ut. Med finansiering frå Statens Landbruksbank har Planteforsk Ullensvang i samarbeid med Planteforsk Plantevernet gjennomført det eitt-årige prosjektet "Kartlegging av årsaker til tredaude i søtkirsebær" i 1999. Dette var eit oppdrag for Hardanger Frukt og Bær. Kartleggingsarbeidet var delt i to: 1. Kartlegging av 5 bruk som har problem med tredaude blant medlemene til Hardanger Frukt og Bær med utttak og analyse av nematode-, sopp-, virus- og jord- og bladprøvar saman med feltinspeksjonar. 2. Spørjeundersøking til søtkirsebærdyrkarar ved 5 fruktlager i Ullensvang om tilhøve som kan tenkjast å påverka tredaude i søtkirsebær . I desse fem søtkirsebærhagane, var næringstilstanden av makronæringsemne i jorda høg og delvis over det optimale. Ubalanse mellom næringsemna kan vera med og svekka trehelsa til trea. Grupper av rotnematodar som gjer skade på frukttrea var registrert i alle hagane og kan såleis vera medverkande til symptoma. Det var også mogeleg å relatera høge populajonar av rotsårnematodar til dårleg tilvekst og høge spiralnematodetal til tidlegare observasjonar av tredaude. Det vart ikkje påvist at ulike insekt, soppar, bakteriar eller virus var primærårsak til denne tredauden. Grundigare undersøkingar og då særleg av nematodar i jorda bør utførast vidare for å påvisa årsaker til denne tredauden i søtkirsebær og finna mogelege rådgjerder for å bekjempa dei ulike potensielle skadegjerarane.  Spørjeundersøkinga viste at mange søtkirsebærdyrkarar meinte det var skilnad mellom kor utsette ulike sortar og grunnstammer var for tredauding i frukthagane. Gjenplanting på same arealet kort tid etter at det var rydda steinfruktplanting fremja tredauding. Lauvtrebarkbillen var årsak til tredaude, men då er diagnosen oftast enkel å stilla. Kulturmåten som gjødslings- og vatningspraksis verkar mindre inn, men vass-sig på trerøtene var negativt.

Sammendrag

Den nordlige rotgallnematoden, Meloidogyne hapla, er så langt påvist på friland i Vestfold, Aust-Agder og Rogaland, men bør ha mulighet til å etablere seg i hvert fall opp til og med Nord-Trøndelag. Nematoden lever parasittisk i røttene på et stort antall plantearter, inkludert de fleste grønnsaker. Skader i gulrotsåkre har vist redusert vekst eller total utgang av kulturveksten. Gulrøttene kan bli misdannet, avstumpet, og danne flere spisser. Galler finnes både på hovedroten og siderøttene. I kepaløk er skade registrert som flekkvis redusert vekst. Skadeterskelen for gulrot og kepaløk er under l egg pr. gram jord. Gulrot er mer følsom enn kepaløk på grunn av både kvantitets- og kvalitetsreduksjon. Mens de fleste grønnsaker er gode vertsplanter, og dessuten følsomme for angrep av M. hapla, kan de fleste korn og grasarter karaktriseres som ikke-vertsplanter. Tilsåing med korn og gras kan derfor redusere smittenivået. Dette krever imidlertid et nøye ugrasrenhold da M. hapla er kjent for å angripe over 50 vanlige arter av ugras. De påvisninger som er gjort i de senere år kan indikere en begynnende spredning på frilandsarealer. Man bør være observant ovenfor denne nematoden i årene fremover slik at spredning og skadeomfang kan holdes under kontroll.

Sammendrag

The VEAS-Biosolids are intended as fertilizers and soil improvers in agriculture. The Norwegian legislation requires that material applied to agricultural land should pose no threat to human, animal and plant health. This may include freedom from infective plant pathogens of certain species, and specified limits for the occurrence of viable seeds of weeds. In the present study, the sanitation efficacy for potato cyst nematode (PCN), Globodera rostochiensis (Ro1) and wild oat, Avena fatua, is evaluated for the VEAS combined thermal filter press and vacuum dryer, which is the final step in the production of VEAS-Biosolids at the VEAS sewage sludge industrial plant. Germ carriers, each carrying 3 nylon bags with 20 nematode cysts and one bag with 100 seeds of wild oat, were placed in 3 filter presses at the VEAS plant. The germ carriers for in-process testing and the non-exposed process control germ carriers were either pre-exposed to sludge or kept dry before the test run. During this test, the pathogens were exposed to temperatures of 78-81 oC for 145 minutes and pressure variations between 4,5 and -0,92 bar. After completion of the test the germ carriers were removed, and the survival of PCN and wild oat seeds was investigated in the laboratory. The vitality of PCN was studied by recording the hatching of juveniles, by vitality staining of cyst contents with New Blue R, and by recording the development of new cysts on a susceptible potato cultivar. The viability of wild oat examined by tetrazolium test. Under the conditions of present test run and according to the vitality tests performed, the combined thermal filter press and vacuum dryer of the VEAS industrial plant had a 100% efficacy in the sanitation of PCN and wild oat. For both organisms a 4 days pre-exposure to sludge seemed to reduce vitality and viability. The mechanism of sanitation may rely on an interaction between sludge toxicity, temperature and pressure changes. Under the conditions of the test run the VEAS combined thermal filter press and vacuum dryer was reliable in eradicating PCN and wild oat.

Til dokument

Sammendrag

Damping av jord er en gammel metode for bekjempelse av ugras, sopp, nematoder og virus. Desinfeksjon ved hjelp av damp ble tatt i bruk allerede i begynnelsen av forrige århundre, men det var først i begynnelsen av dette århundre metoden ble benyttet i større omfang, og da spesielt i veksthus. I motsetning til de kjemiske desinfeksjonsmidlene, hadde damping en mer universell virkning ved sin effekt både på ugrasfrø, nematoder, sopp og virus. Damping ble derfor av mange sett på som den beste metoden for desinfeksjon av jord (Newhall et al., 1931, og Baker, 1950). Etter hvert overtok imidlertid de kjemiske midlene markedet, og utviklingen av dampingsteknikken stoppet opp. Det er derfor relativt lite nyere litteratur og forsøksresultater fra bruk av jorddamping

Sammendrag

Flere arter cystenematoder (rundormer) i slekten Heterodera angriper korn. Den vanligste og kanskje viktigste arten er havrecystenematoden H. avenae (CCN) som har vært kjent i Norge siden 1925. Korndyrkingen i Norge domineres av bygg fulgt av havre og hvete. Hvetearealet har i perioden 1985-1995 økt med 70%. Feltskader av CCN vises som flekker med ujevn vekst, hvilket er særlig tydelig i havre. I tillegg til korn er flere arter av gras også vertsplanter til CCN. Det presenterte arbeidet gir en bakgrunn for problematikken omkring cystenematoder i korn, og rapporterer om utbredelsen av slekten Heterodera i kornfelt i Norge. Resultatene bygger på 218 prøver analysert i perioden 1995-1998. Nematoder i slekten Heterodera er registrert fra Rogaland til en posisjon 65,5oN i Nordland. Havre og hvete viser de høgste forekomstene. Det er notert et økt skadeomfang de senere årene. Tidligere studier har vist at CCN patotype Ha 51 har dominert i Norge. Et økt skadeomfang kan skyldes at resistensen mot Ha 51 ikke er vedlikeholdt i nyere sorter, og at det er en forskyving av patotype-spektret innen CCN. Et økt hveteareal og dyrking av mottakelig korn før havre eller hvete kan også være medvirkende årsaker. Kunnskapen om dagens art- og patotype-spekter blant korncystenematodene i Norge må økes. Det er viktig å kartlegge forekomst av resistens mot cystenematoder i dagens kornsorter, og utvikle strategier for en effektiv bekjempelse.

Sammendrag

Nematodes (roundworms) are microscopic vermiform animals. Most nematodes live in soil or in fresh water and marine sediments. Nematodes (Phylum Nematoda) has experienced more than 600 million years of evolution and form 80% of the multicellular animals on planet earth. The population densities of nematodes often reach several million individuals per m2. Most species are free-living, feeding on microorganisms, microscopic plants and animals. Numerous species, however, are parasites of humans, animals and plants. Nematodes may be beneficial to man as regulators of nutrient cycling or as parasites of insect pests. The study of plant parasitic nematodes, nematology, is a young scientific dicipline. Although, the first plant parasitic nematode, i.e. the wheat seed-gall nematode Anguina tritici, was observed as early as in 1743, nematology as a science did not develop until the second half of the 19th century. The economic impact of nematodes as parasites of agricultural crops was recognised as late as in the 1940:ties, and was a consequence of the increased use of chemicals. The economic loss caused by nematodes to world agriculture may amount to 80 billion US$ annually. Plant parasitic nematodes are of particular importance in tropical and subtropical regions of the world. At present the full importance of these parasites may be much underestimated due to the frequent use of nematicides. However, as a result of future restrictions in the use of chemical treatments against nematodes, the damage caused by these parasites can be expected to increase dramatically. Future successful management of both harmful and beneficial nematodes would require increased knowledge of nematode biology. This can only be achieved by an increased research and education in nematology.

Sammendrag

Soil samples from a growth depression in potato (cv. Saturna) yielded large numbers of root lesion nematodes Pratylenchus penetrans. Growth was greatly reduced in the center of the patch, but improved gradually towards the margins. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans. The nematode density in the central part of the patch was 900/250g of soil, compared to 49/250 g of soil in the margins, where plant growth seemed unaffected. Our data suggest a threshold for damage of 100-250 P. penetrans per 250 g of soil. P. penetrans was present in roots, underground stems, stolons and tubers. In tubers nematodes occurred in the outermost 0.5 mm of the tissue. Common scab (Streptomyces spp.) occurred frequently, and P. penetrans was also present in tubers with scab. The nematodes were found around and inside cross-fissure lesions considered typical of Streptomyces. Saturna has a relatively high degree of tolerance against common scab. The high frequency of scab, and close association of the nematodes with the symptoms could indicate an interaction. This study suggests that Norway may have a new problem in potato production. Our study confirms that P. penetrans survives storage of seed potatoes, from which new infestations develop. Hence, tubers do appear to be an important means for the spread of P. penetrans to new areas.

Sammendrag

På fotballbaner i Norge er kroknematode Subanguina radicicola, stuntnematode Tylenchorhynchus dubius, grascystenematode Punctodera punctata, rotsårnematoder Pratylenchus spp. og ringnematoder (fam. Criconematidae) blitt påvist i forbindelse med skader på gras. Nematodangrep er rapportert å kunne gi mer enn 90 % vekstreduksjon på gras. Krypkvein Agrostis stolonifera, engrapp Poa pratensis, tunrapp Poa annua og engelsk raigras Lolium perenne er viktige grasarter som skades sterkt av nematoder. Nematodeangrep kan gjøre plantene mer følsomme for angrep av mikroorganismer, samt slitasje og annet abiotisk stress. De viktigste spredningsveiene for nematoder er maskiner, jord fra åker og idrettsanlegg, og ferdigplen. Forebyggende tiltak er den beste strategien for å unngå smitte av nematoder, inkludert bl. a. hygiene, rent plantemateriale og jorddesinfeksjon. Smittede anlegg kan forhindre videre smittespredning gjennom god hygiene og regulert maskinsamarbeide. Tiltak baseres på jordprøvetaking for nematoder. Kunnskapen om planteparasittære (skadelige) nematoders biologi i graskulturer er viktig for å kunne opprettholde og forbedre kvalitet og herdighet hos ulike typer av gras. Språk: Svensk.