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Abstract

The solitary parasitic wasp Lysiphlebus testaceipes, is a species native to North America. The species has a broad aphid host range and has been accidentally spread or introduced as a biocontrol agent to many regions of the world. In Benin, L. testaceipes is a newly found species, and it is the dominating primary parasitoid of aphids on vegetables.

Abstract

Two Malaise traps were set up at Ås, Southern Norway, during the growing seasons 1992-1997, one trap in an organic grown barley field and one in its boundary. Totally 23 species of Tipulidae (Diptera) were identified, of these eight species belonged to the genus Nephrotoma Meigen, 1803. Of the total specimens collected 93% of the males and 88% of the females belonged to this genus. Comparing the two traps, 80% of the Nephrotoma specimens were recorded in the organic field. It is discussed if larvae of Nephrotoma spp. in Norway can be potential pests in agricultural crops as reported from other countries. To Malaisefeller ble plassert ut i Ås i vekstsesongene 1992-1997, en i en økologisk dyrket byggåker og en i kanten av åkeren. Totalt ble 23 arter av stankelbein (Tipulidae, Diptera) identifisert, 8 av disse tilhørte slekten Nephrotoma. Av det totale antall individer som ble samlet inn, var 93 % av hannene og 88 % av hunnene av slekten Nephrotoma. 80 % av Nephrotoma-individene ble funnet i den fellen som sto ute i byggåkeren. I mange andre land er larver av Nephrotoma-arter skadedyr på mange kulturplanter i jordbruket, og det diskuteres om disse artene kan opptre som skadedyr i Norge.

Abstract

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 ...

Abstract

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

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Abstract

Apple fruit moth Argyresthia conjugella is a specialist seed predator of rowan Sorbus aucuparia. Large-scale synchronous fluctuation of seed production in rowan (i.e. named masting) drives the apple fruit moth to seek alternative host plants such as apple, during years when rowan berries are not available for oviposition. The role of plant volatile compounds in the attraction of gravid apple fruit moth females is studied in a laboratory wind tunnel. Volatiles from rowan branches with green berries stimulate female moths to fly upwind and to land at the odour source. By contrast, females are not attracted to rowan branches without green berries, and they are not attracted to apple, demonstrating that the chemical stimulus from rowan berries is required for attraction. Attraction to synthetic compounds identified from rowan, anethole and 2-phenyl ethanol confirms the role of plant volatiles in host finding. These two compounds, however, show a discrepant behavioural effect in wind tunnel and field tests. Field traps baited with 2-phenyl ethanol capture female moths but anethole does not produce significant captures. Wind tunnel tests produce the opposite results: moths fly upwind towards the anethole lure, whereas 2-phenyl ethanol is not attractive at all. Wind tunnel attraction to 2-phenyl ethanol is achieved by adding odour from a rowan branch without berries, which is not attractive on its own. This finding demonstrates that interaction with the background odour contributes to the behavioural effect of plant volatile stimuli in the field.

Abstract

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.

Abstract

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.

Abstract

The egg parasitoid O. epuhts and the pupal parasitism caused by the P. foveolatus and Mesopolobus spp. were the key mortality factors in the population dynamics of the C. similis. The egg and pupal parasitism were density dependant at two and one locality, respectively. (c) 2007 Elsevier Ltd. All rights reserved.

Abstract

Vi undersøkte fenologi og kjønnsratio (andel hunner) til 15 arter snylteveps som parasitterer havrebladminerflue i Norge. Studiet gikk over 6 sesonger i byggskiftet i et økologisk drevet felt ved Norges Landbrukshøyskole, og det ble brukt Malaisefeller som innsamlingsmetode (en i åkerkanten og en 60 m inn i byggskiftet). Resultatene tydet på at snyltevepshunnene var mer knyttet til kanten enn hannene og verten sin, og at mange av snyltevepsene vandret ut av åkeren en stund før tresking. De to vanligste snyltevepsartene var Cyrtogaster vulgaris (en puppeparasitt) og Diglyphus begini (en larveparasitt). Førstnevnte hadde en særlig nær tilknytning til kanten, og tidligere studier har vist at denne kan overvintre som voksen i f.eks grastuer i kanten. Hos sistnevnte fant vi en tetthetsavhengig kjønnsratio i fellefangstene: Jo flere individer i fellene, jo lavere andel var hunner

Abstract

In the present study the predation rate of Chrysoperla carnea (Stephens) on eggs and larvae of the lepidopterous species Mamestra brassicae (L.) was investigated including the prey"s influence on survival and development. The experiments were done at 20 +/- 1 degrees C and L:D = 16:8. C. carnea larvae were fed on eggs and first instar larvae of M. brassicae, respectively. In both cases the daily predation rate of C. carnea increased slowly during the two first instars and reached a peak in the third larval instar. During the third instar 87% and 85% of the total numbers of M. brassicae eggs and larvae, respectively, were consumed. C. carnea preyed on a mean total of 312 M. brassicae eggs and 232 M. brassicae larvae during its larval development. The mean daily predation rate of C. carnea reached a maximum of 106.6 eggs of M. brassicae and 46.1 larvae of M. brassicae. C. carnea consumed a total of 32 mg of M. brassicae eggs and 70 mg of M. brassicae larvae during its larval development. The developmental time of C. carnea fed on M. brassicae eggs and larvae was 27.4 and 21.5 days, respectively. Almost 10% of C. carnea died when reared on M. brassicae eggs and 15% died when reared on M. brassicae larvae. The quality aspect of the prey is discussed.