Til dokument

Sammendrag

Coffee is an important commodity for Kenya, where production is steadily declining, despite a global rise in demand. Of the various constraints affecting production, plant-parasitic nematodes are a significant, but often overlooked, threat. As a perennial crop, treating plantations once infected with nematodes becomes difficult. The current study evaluated the drenching application of two biocontrol agents, Trichoderma asperellum and Purpureocillium lilacinum, for their nematode control efficacy, as well as their impact on the soil nematode community structure on mature, established coffee trees in Kenya. Seven Arabica coffee field trials were conducted over two years on trees of various ages. All the fields were heavily infested with Meloidogyne hapla, the first report of the species on coffee in Kenya. Both fungal biocontrol agents were detected endophytically infecting roots and recovered from soil but not until six months after initial applications. The population densities of M. hapla had significantly declined in roots of treated trees 12 months after the initial application, although soil nematode density data were similar across treatments. Based upon the maturity index and the Shannon index, treatment with T. asperellum led to improved soil health conditions and enrichment of diversity in the microbial community. Application of P. lilacinum, in particular, led to an increased abundance of fungivorous nematodes, especially Aphelenchus spp., for which P. lilacinum would appear to be a preferred food source. The soils in the trials were all stressed and denuded, however, which likely delayed the impact of such treatments or detection of any differences between treatments using indices, such as the functional metabolic footprint, over the period of study. A longer period of study would therefore likely provide a better indication of treatment benefits. The current study positively demonstrates, however, the potential for using biologically based options for the environmentally and climate-smart management of nematode threats in a sustainable manner on established, mature coffee plantations.

Til dokument

Sammendrag

Potato Cyst Nematodes (PCN) (Globodera rostochiensis and G. pallida Woll.) are quarantine pests of potato (Solanum tuberosum L.) worldwide capable of causing significant yield loss and difficult to manage with conventional methods. The study explored the diversity of antagonistic fungi associated with PCN obtained from soil samples collected in Nyandarua and Nakuru Counties in Kenya and their effect on PCN egg viability and hatching was also evaluated. Twelve fungal isolates from five genera were isolated and characterized using morphological and molecular techniques. The twelve isolates were Trichoderma asperellum (4), T. hamatum, T. breve, T. atrobruneum, Amanita basiorubra, Setophoma terrestris (2), Penicillium chrysogenum and Clonostachys rosea. The most abundant isolate was Trichoderma spp. with 58 % occurrence. The effect of seven of the isolates on PCN eggs showed that T. breve and P. chrysogenum reduced egg viability by 41 % and 34 %, respectively while T. asperellum and T. breve reduced their hatching by 50 % on average. Trichoderma atrobrunneum, T. hamatum, and A. basiorubra also reduced the PCN egg viability by 27 % on average. These fungal isolates could provide a potential tool for PCN management in potato production systems for improved yields. However, further studies are warranted to validate these findings under greenhouse and field conditions. A more comprehensive bioprospecting survey for PCN associated antagonistic fungi needs to be extended to other potato growing regions to explore further cyst pathogens.

Til dokument

Sammendrag

The root-burrowing nematode, Radopholus similis, is reputedly the most damaging nematode pest of banana and responsible for major production losses. In this study, the endophytic potential of 13 fungal isolates was assessed for the management of R. similis in East African Highland bananas (‘Ng’ombe’). All isolates successfully colonised tissue-cultured banana roots, with isolates from Trichoderma, Fusarium and Hypocrea producing the highest (⩾49.1%) and Beauveria isolates the lowest (⩽14.4%) colonisation. The fungal endophytes T. asperellum (ICIPE 700) and H. lixii (ICIPE 697) were the most effective in reducing R. similis densities (>81%) relative to the non-inoculated control. However, the combined inoculation of ICIPE 700 and ICIPE 697 led to greater suppression of R. similis (>21%) relative to individual inoculation. Suppression of R. similis following inoculation of banana roots with ICIPE 700 and/or ICIPE 697 was associated with the significant upregulation of the defence-related gene PR-1, the cell signalling gene calmodulin Ca2+ and the cell-wall-strengthening gene β-1,3-glucan synthase. This study demonstrates the potential for nematode management in bananas with fungal endophytes, especially using the isolates ICIPE 700 and ICIPE 697 when combined.

Sammendrag

Overvåkingsprogrammet i 2022 omfattet undersøkelse for tilstedeværelse av furuvednematode (Bursaphelenchus xylophilus) i hogstavfall fra furu og i furubukker av slekten Monochamus. I OK-programmets delaktivitet som omfattet kartlegging av furuvednematode i hogstavfall, ble det tatt 401 flisprøver fra hogstavfall og vindfall av furu (Pinus sylvestris) som hadde tegn på angrep av furubukker i slekten Monochamus. Prøvene ble tatt i Innlandet, Vestfold og Telemark, og Viken. Flisprøvene ble inkubert ved +25°C i to uker før nematoder ble ekstrahert med Baermann-trakt og undersøkt i mikroskop. Furuvednematoden B. xylophilus ble ikke påvist, men den naturlig forekommende arten Bursaphelenchus mucronatus kolymensis ble oppdaget i 16 flisprøver. Siden overvåkingen av furuvednematode startet i 2000, har alle de analyserte flisprøvene, totalt 8924, vært negative for furuvednematode. I OK-programmets delaktivitet som omfattet kartlegging av furuvednematode i furubukker, ble feller med attraktanter for fangst av voksne, flygende furubukker satt opp i Agder, Telemark, Viken (Østfold og Akershus), Hedmark og Trøndelag. Billene ble kuttet i biter og ekstrahert med en modifisert Baermann-trakt. Suspensjonen fra ekstraksjonene ble undersøkt i mikroskop for forekomst av Bursaphelenchus spp. Ingen furuvednematoder ble påvist i de 54 undersøkte billene. Bursaphelenchus mucronatus kolymensis ble ikke heller oppdaget.

Til dokument

Sammendrag

The legume cavalcade, Centrosema pascuorum, is used extensively as a cover crop and as a component of conservation agriculture systems. It is also an attractive rotation or cover crop for the management of root-knot nematodes (RKN; Meloidogyne spp.) as it is a non-host. RKN are persistent pests that are well known to be difficult to control. However, the mechanisms governing the non-host status of cavalcade is unknown. The current study established that cavalcade leaves are toxic to RKN as either aqueous extracts or soil amendments. Bioassays conducted using Meloidogyne javanica showed that a 90% concentration of aqueous extract derived from 1-month-old cavalcade leaves (89 mg crude extract ml−1) suppressed nematode hatch (82.9%) and killed infective second-stage juveniles of M. javanica (85.3%). Soil amendments with 1% (w/w) of 1-month-old cavalcade leaves (0.99 mg crude extract g−1 soil) also provided effective control of M. javanica in the glasshouse on okra. One-month-old leaves appeared more effective than 2- or 3-month-old leaves. The soil amendments had no adverse phytotoxic effect on okra seed germination. Our study demonstrates the potential for using cavalcade leaves or extracts to manage RKN. This may be due to the nematicidal activity of the various compounds in the leaves, such as flavonoids, phenols and terpenoids, which should be further assessed.

Til dokument

Sammendrag

The banana weevil (Cosmopolites sordidus) and the burrowing nematode Radopholus similis represent two of the most important pests of bananas. Previously, colonization of banana plants by the non-pathogenic Fusarium oxysporum (isolate V5w2) and the entomopathogenic Beauveria bassiana (isolate WA) have been shown to increase host resistance to various banana pests and diseases. However, there is limited data on how the combined inoculation of these isolates would affect field performance of bananas. In this study, the fungal endophytes were inoculated separately and in combination. Tissue cultured plantlets of cooking banana cultivar Mbwazirume and dessert banana cultivar Grande Naine were inoculated by root drenching with a suspension of 1.0 × 107 spores mL−1 of the endophytes on three occasions, separated 4 weeks apart, before transplanting into the field. Each plantlet was further inoculated with 1800 nematodes, composed primarily of R. similis. Inoculation of banana plants with the fungal endophytes significantly reduced nematode densities by >34%. Similarly, plant toppling was lower in the endophyte-enhanced plants (<16.5%) compared with the control (23.3%). We also observed improved yield of the first crop cycle in the endophyte-enhanced plants, which yielded >11 t ha−1 year−1 versus 9 t ha−1 year−1 achieved in the non-inoculated plants. These findings demonstrate the benefits of fungal endophytes in improving the yield of both cooking and dessert bananas via suppression of nematode densities and nematode-related damage.

Til dokument

Sammendrag

The success of Phasmarhabditis hermaphrodita (Schneider) Andrássy (Rhabditida: Rhabditidae) as a biological control agent of molluscs has led to a worldwide interest in phasmarhabditids. However, scant information is available on the lifecycle development of species within the genus. In the current study, the development of P. hermaphrodita, Phasmarhabditis papillosa, Phasmarhabditis bohemica and Phasmarhabditis kenyaensis were studied using ex vivo cultures, in order to improve our understanding of their biology. Infective juveniles (IJs) of each species were added to 1 g of defrosted homogenized slug cadavers of Deroceras invadens and the development monitored after inoculated IJ recovery, over a period of eight–ten days. The results demonstrated that P. bohemica had the shortest development cycle and that it was able to produce first-generation IJs after eight days, while P. hermaphrodita, P. papillosa and P. kenyaensis took ten days to form a new cohort of IJs. However, from the perspective of mass rearing, P. hermaphrodita has an advantage over the other species in that it is capable of forming self-fertilizing hermaphrodites, whereas both males and females are required for the reproduction of P. papillosa, P. bohemica and P. kenyaensis. The results of the study contribute to the knowledge of the biology of the genus and will help to establish the in vitro liquid cultures of different species of the genus.

Til dokument

Sammendrag

The success of the mollusc-parasitic nematode, Phasmarhabditis hermaphrodita (Schneider) Andrássy (Rhabditida: Rhabditidae), as a biological control agent in Europe has led to worldwide interest in phasmarhabditids as biocontrol agents. In this study, the mass culture potential of three phasmarhabditids, namely Phasmarhabditis papillosa, Phasmarhabditis kenyaensis and Phasmarhabditis bohemica, was assessed. In addition, ten bacterial candidates, consisting of seven associated with slugs and three associated with entomopathogenic nematodes, were investigated. The bacteria were tested for their ability to cause mortality to Deroceras invadens, as well as to support nematode growth. Initial mortality studies demonstrated that Kluyvera, Aeromonas and Pseudomonas spp. (AP3) caused 100% mortality when they were injected into the haemocoel of D. invadens. However, in growth studies, Pseudomonas sp. (AP4) was found to be the most successful bacterium, leading to recovery and reproduction in almost all nematode species, except for P. kenyaensis. In flask studies, P. bohemica, which showed exceptional growth with Pseudomonas sp. (AP1), was chosen for further investigation. The effect of inoculating flasks with different concentrations of Pseudomonas sp. (AP1), as well as with different concentrations of P. bohemica, was evaluated by assessing the nematode populations for 14 days. The results indicated that the lowest, 1% (v/v), bacteria inoculation led to higher total nematode and to infective juvenile (IJ) yield, with flasks with the highest IJ inoculum (3000 IJs/ml) having a positive effect on the total number of nematodes and IJs in cultures of P. bohemica. This study presents improvements for the mass-culturing of nematodes associated with molluscs.

Sammendrag

Phytophthora- og nematode-forekomst ble kartlagt langs E39 mellom Staurset og Stormyra i Heim kommune (Trøndelag) i september 2022 i forbindelse med planlagt utvidelse av veien, samt langs foreslått ny vegtrasé som krever betydelige terrenginngrep. Phytophthora er en slekt med fremmende, invaderende planteskadegjørere som angriper og ødelegger røttene til tre- og urteaktige planter. Nematoder er en annen organismegruppe som parasitter planter og kan gi alvorlige tap i jordbruksavlinger eller skog. Innenfor disse to gruppene av jordboende planteskadegjørere er det noen få arter som har status som karanteneskadegjørere, mens de fleste blir betegnet som kvalitetsskadegjørere. Felles for dem er at man må unngå spredning til nye steder ifølge Matloven og Naturmangfoldloven, men i tillegg er det rapporteringsplikt til Mattilsynet for karanteneskadegjørere. Begge gruppene av planteskadegjørere kan spres ved flytting av jordmasser. Phytophthora-prøvene besto av jord-, blad- og en vevsprøve fra gråor som ble tatt ut i områder med trevegetasjon langs vassdrag både oppstrøms og nedstrøms for veiarbeidet. Nematodeprøvene ble tatt ut fra jordbruksareal og beitemark ved siden av veien. Totalt ble tre Phytophthora-arter påvist i 13 av totalt 20 Phytophthora-prøver tatt ut langs E39: Phytophthora gonapodyides (i 11 prøver), P. gregata (1 prøve) og en uidentifisert Phytophthora-art (1 prøve). Der Phytophthora ble påvist er det stor sannsynlighet for at massene som inneholder jord og røtter fra trevegetasjonen (hovedsakelig gråor) er forurenset. Phytophthora gonapodyides trenger man imidlertid ikke å ta hensyn til når det gjelder flytting av jord siden det er en svak skadegjører som er vanlig i norske vassdrag. Dermed er det bare restriksjoner på flytting av masser ved de to lokalitetene der P. gregata og den uidentifiserte Phytophthora-arten ble funnet. På disse stedene ble det også funnet skader på trær. Nematodeprøvene viste ingen funn av karanteneskadegjørere og heller ikke betydelige funn av andre planteparasittære nematoder. Karanteneskadegjørerne potetcystenematode [PCN] (Globodera rostochiensis og G. pallida) og rotgallnematode [RGN] (Meloidogyne chitwoodi og M. fallax) ble ikke funnet. Rotsårnematoden (Pratylenchus sp.), som kan være problematisk i mengder større enn 250 nematoder/250 ml jord, ble funnet i alle 12 nematodeprøvene, men i så lave antall at det ikke kan anses som et problem. Øvrige nematode-arter som ble funnet var også i så lave antall at de ikke kan anses å være problematiske. Flytting av jord fra jordbruks- og beitearealer kan derfor gjøres uten restriksjoner. I denne kartlegging av Phytophthora- og nematode-forekomst langs E39 mellom Staurset og Stormyra ble det gjort to funn av Phytophthora som innebærer restriksjoner på flytting av masser. Ved de to lokalitetene der P. gregata og den uidentifiserte Phytophthora-arten ble funnet, må massene forbli på/nær opphavsstedet. Dersom disse infiserte masser likevel må flyttes (f.eks. til deponier) er det spesielt viktig at massene ikke legges nær vassdrag eller verna naturområder. Etter at arbeidet er ferdige på steder med infisert jord, må jordrester på maskiner og utstyr vaskes bort før de flyttes til nye områder.

Sammendrag

Potetcystenematodene Globodera rostochiensis og G. pallida (henholdsvis gul og hvit PCN) er definert som karanteneskadegjørere, og er strengt regulert av norsk lov og forskrift. I henhold til forskriften kan poteter fra arealer som er smittet med gul PCN (G. rostochiensis) leveres til mottaksanlegg. Alt avfall fra anlegg som videreforedler potet ansees derfor som spesialavfall, og har frem til nå blitt deponert. For å kunne videreforedle potetavfallet fra produksjonen ønsker Maarud å undersøke om PCN overleverer komposteringsprosessen deres. Det er derfor utført komposteringsforsøk med cyster av gul PCN i varmeskap under kontrollerte temperaturforhold som tilsvarer temperaturene i Maaruds komposteringsprosess. For å påvise om egg og larver inne i cystene overlevde prosessen ble det gjort klekkeforsøk med cystene fra komposteringsforsøket. Resultatene viste at PCN ikke overlevde temperaturforløpet i forsøket. I komposteringsforsøket var temperaturen over 55 ℃ i 18 dager. Det er svært viktig at komposteringsprosessen sikrer at alt avfallet i kompostrankene behandles likt, og at alt avfallet i rankene eksponeres for temperatur over 55 ℃ i minst 18 dager for å sanere PCN. Dersom cyster ikke utsettes for høy nok temperatur over tid, er det betydelig risiko for at PCN overlever.

Til dokument

Sammendrag

Despite their important ecological roles for soil health and soil fertility, free-living nematodes (FLN) have received relatively limited research attention. The present study evaluated the community structure and diversity of FLN in a field setting. The experiments were conducted in on-farm and on-station field plots sown to maize (Zea mays) and beans (Phaseolus vulgaris) under four cropping practices. These farming systems included organic (compost and biopesticide use), conventional (synthetic fertilizer and pesticide applications), farmer practice (organic and synthetic amendments) and a control (non-amended plots). Nineteen genera of free living nematodes, belonging to bacterivores, fungivores, omnivores and predators were recorded. Among these, bacterivores (Cephalobidae and Rhabditidae) were the most dominant group in the organic systems when compared to the conventional and control systems. Farming systems influenced the abundance and diversity of free living nematodes, with the organic farming system having higher values of maturity, enrichment and structural indices than other farming systems. This would indicate greater stability in soil health and improved soil fertility. This implies that the organic farming systems play a key role in improving the biodiversity and population buildup of FLN, compared with other systems. Our study helps to improve our understanding of how farming systems influence soil biodynamics, while studies on the longer-term effects of organic and conventional farming systems on the build-up or reduction of free living nematodes for improved ecosystem services are needed.

Til dokument

Sammendrag

Bio-communication occurs when living organisms interact with each other, facilitated by the exchange of signals including visual, auditory, tactile and chemical. The most common form of bio-communication between organisms is mediated by chemical signals, commonly referred to as ‘semiochemicals’, and it involves an emitter releasing the chemical signal that is detected by a receiver leading to a phenotypic response in the latter organism. The quality and quantity of the chemical signal released may be influenced by abiotic and biotic factors. Bio-communication has been reported to occur in both above- and below-ground interactions and it can be exploited for the management of pests, such as cyst nematodes, which are pervasive soil-borne pests that cause significant crop production losses worldwide. Cyst nematode hatching and successful infection of hosts are biological processes that are largely influenced by semiochemicals including hatching stimulators, hatching inhibitors, attractants and repellents. These semiochemicals can be used to disrupt interactions between host plants and cyst nematodes. Advances in RNAi techniques such as host-induced gene silencing to interfere with cyst nematode hatching and host location can also be exploited for development of synthetic resistant host cultivars.

Til dokument

Sammendrag

Plant-parasitic nematodes (PPN) cause significant yield reduction in commercial pineapple (Ananas comosus) worldwide. In Kenya, few nematode studies have been conducted, although the main commercial pineapple producer has sole dispensation to use Telone II (1,3-Dichloropropene) indicating the magnitude of the nematode problem. This study was conducted with the aim to investigate the population densities and diversity of nematodes in two commercial plantations with two contrasting management practices. We additionally assessed the influence of crop age and compared this with nearby smallholder pineapple production systems. Soil and root samples were collected from fields of different ages in each commercial plantation and from 29 smallholder fields. A total of 18 genera were associated with pineapple, with a relatively greater diversity found in smallholder than commercial farms. The most prevalent genus was Meloidogyne spp. (M. javanica) followed by Helicotylenchus spp., Tylenchus spp. and Aphelenchoides spp. PPN densities were higher in relatively older fields of 24 and 36 months than from fallow and 3-month-old fields. Regression analysis additionally demonstrated the rise of PPN densities with age of pineapple fields, especially Meloidogyne spp., while free-living nematode densities declined. This study provides an indication of the high level of PPN infection in pineapple in Kenya, which would constitute an important factor contributing to low yields. The study confirms an obvious need for pineapple producers to control PPN to improve crop yields.

Til dokument

Sammendrag

The banana weevil (BW), Cosmopolites sordidus, is the main coleopteran pest of banana, causing up to 100% yield loss. In this study, we screened 20 isolates of entomopathogenic fungi (EPF) for the management of BW. In the lab, eight Beauveria bassiana isolates caused >50% mortality of the adult BW, whereas Metarhizium anisopliae and Isaria fumosorosea isolates were less pathogenic. B. bassiana isolates ICIPE 648, ICIPE 660 and ICIPE 273 were the most pathogenic, killing ≥80% of adult BW. B. bassiana isolate ICIPE 622 yielded the highest spores per BW cadaver (1.84 × 108 spores), followed by ICIPE 660, ICIPE 273 and ICIPE 648—1.17 × 108, 3.8 × 107 and 3.6 × 107 spores, respectively. ICIPE 273 had the shortest LT50 (5.3 days) followed by ICIPE 648 (9.8 days) and 660 (11.1 days). Similarly, the LC50 values for the three isolates were 5.18 × 107, 5.49 × 107 and 5.2 × 107 spores mL−1, respectively. In the field, ICIPE 273 and ICIPE 648 had the highest (31.3%) and lowest (20.8%) pathogenicity, respectively. This study indicates that the B. bassiana isolates ICIPE 273, ICIPE 648 and ICIPE 660 are potential candidates for the environmentally sustainable management of BW.

Til dokument

Sammendrag

A new species of Phasmarhabditis was isolated from the slug, Polytoxon robustum, from Nairobi, Kenya. The nematode was identified using morphological, morphometric, molecular and phylogenetic analyses. Phasmarhabditis kenyaensis n. sp. is characterised by an infective juvenile with the longest body length in the genus, measuring 1232 (1107-1336) μm, by the presence of males with a bursa bearing nine bilateral pairs of genital bursal papillae and one pair of papilliform phasmids flanking the tail, cephalate paired spicules, with an arc length of 71 (57-81) μm, as well as by females with a vulva located at the mid-body region and a conoid tail shape, with two phasmids located at ca 40% of the tail length. The molecular phylogeny of the new species, as inferred from its SSU (small subunit) rRNA gene, places P. kenyaensis n. sp. genetically close to undescribed phasmarhabditids from South Africa, suggesting an African grouping, while the D2-D3 (large ribosomal subunit) and ITS region analyses relate P. kenyaensis n. sp. to P. meridionalis, with weak bootstrap support. This is the third new Phasmarhabditis species described from the African continent, the new species bringing the total known complement of the genus to 14 species. A morphometric compendium to all species cultured in vivo is supplied.

Til dokument

Sammendrag

Enset (Ensete ventricosum), is a perennial herbaceous plant belonging to the family Musaceae, along with banana and plantain. Despite wild populations occurring in eastern, central and southern Africa, it is only in Ethiopia that the crop has been domesticated, where it is culturally and agriculturally symbolic as a food security crop. Although an under-researched orphan crop, enset serves as a staple food for about 20% of the Ethiopian population, comprising more than 20 million people, demonstrating its value in the country. Similar to banana and plantain, enset is heavily affected by plant-parasitic nematodes, with recent studies indicating record levels of infection by the root lesion nematode Pratylenchus goodeyi. Enset is propagated vegetatively using suckers that are purposely initiated from the mother corm. However, while banana and plantain suckers have proven to be a key source of nematode infection and spread, knowledge on the infection levels and role of enset suckers in nematode dissemination is lacking. Given the high levels of plant-parasitic nematodes reported in previous surveys, it is therefore speculated that planting material may act as a key source of nematode dissemination. To address this lack of information, we assessed enset planting material in four key enset growing zones in Ethiopia. A total of 340 enset sucker samples were collected from farmers and markets and analyzed for the presence of nematodes. Nematodes were extracted using a modified Baermann method over a period of 48 h. The root lesion nematode P. goodeyi was present in 100% of the samples, at various levels of infection. These conclusive results show that planting material is indeed a key source of nematode infection in enset, hence measures taken to ensure clean suckers for planting will certainly mitigate nematode infection and spread. The effect of nematode infection on yield and quality on enset remains to be investigated and would be a way forward to complement the nematode/disease studies conducted so far and add valuable knowledge to the current poorly known impact of pests and diseases.

Til dokument

Sammendrag

Pratylenchus goodeyi appears to be the most prevalent nematode pest of enset in Ethiopia, where it can occur in extremely high densities. However, the damage to yield or how different enset cultivars react to the nematode has yet to be determined. The current study therefore sought to establish a first assessment of these reactions by enset to P. goodeyi infection. Determining pest resistant cultivars is an important task in developing management strategies. Our study evaluated nine enset cultivars to establish host response and identify potential sources of resistance. In addition, the pathogenicity of P. goodeyi was assessed on three enset cultivars. After 9 months’ growth, significant differences in final population densities (Pf) and reproduction factor (RF) were observed amongst the nine cultivars, with ‘Gefetanuwa’ the most susceptible (Pf = 25 799 and RF = 12.9), and similarly in a repeat experiment for 4.5 months (Pf = 126 534 and RF = 63.3). ‘Maziya’ and ‘Heila’ were the most resistant in the first experiment (Pf < 455 and RF < 0.2) as well as in the repeat, together with ‘Kellisa’ (Pf < 5255 and RF < 2.6). In the pathogenicity experiment four inoculum densities significantly affected the Pf and RF but not among the three cultivars ‘Maziya’, ‘Arkiya’ and ‘Heila’. This is the first known study to assess genotype reaction to P. goodeyi, which shows that there are significant differences in the reactions of different cultivars and that resistance appears to be present in enset.

Til dokument

Sammendrag

A survey of helminths associated with terrestrial slugs focusing on the invasive Arion vulgaris and the native A. ater was conducted on populations from France, Germany, Netherlands, Norway and Poland. In total, 648 terrestrial slugs were collected from 18 sample sites, and identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. In addition to A. vulgaris and A. ater, also A. vulgaris/A. rufus hybrids and A. ater/A. rufus hybrids were collected. Helminth species were identified based on morphological features and sequencing of the 18S and ITS rDNA regions. The parasites included four nematode species: Alloionema appendiculatum, Angiostoma sp., Phasmarhabditis hermaphrodita, Entomelas sp., two trematode species: Brachylaima mesostoma, Eurytrema sp., and one cestode (tapeworm) species: Skrjabinia sp. Alloionema appendiculatum was the most common helminth in the investigated slug populations. Furthermore, we found higher prevalence of trematodes in the invasive A. vulgaris compared with the native A. ater, while differences in the prevalence for nematodes were not as clear.

Til dokument

Sammendrag

Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.

Til dokument

Sammendrag

Potato cyst nematodes (PCN), such as Globodera rostochiensis and Globodera pallida, are quarantine restricted pests of potato causing major yield and financial losses to farmers. G. rostochiensis was first reported from Kenya’s key potato growing area in 2015. We sought to determine the diversity, prevalence and distribution of PCN species across the country by conducting a country-wide survey between 2016 and 2018, which included a more focused, follow-up assessment in three key potato growing counties. A total of 1,348 soil samples were collected from 20 potato growing counties. Information regarding local potato farming practices, potato cultivar use, their diversity and availability was also recorded. PCN cysts were obtained from 968 samples (71.8%) in all the counties surveyed, with Nyandarua County recording the highest PCN field-incidence at 47.6%. The majority of PCN populations, 99.9%, were identified as G. rostochiensis, while G. pallida was recovered from just one field, in a mixed population with G. rostochiensis. Inconsistencies in PCR amplification efficiency was observed for G. rostochiensis using the recommended EPPO primers, compared with ITS primers AB28/TW81, indicating that this protocol cannot be entirely relied upon to effectively detect PCN. Egg density in Nyandarua County varied between 30.6 and 158.5 viable eggs/g soil, with an average egg viability of 78.9 ± 2.8% (min = 11.6%, max = 99.9%). The PCN-susceptible potato cultivar named Shangi was the most preferred and used by 65% of farmers due to its shorter dormancy and cooking time, while imported cultivars (Destiny, Jelly, Manitou, and Markies) with resistance to G. rostochiensis were used by 7.5% of farmers due to unavailability and/or limited access to seeds. Thus, most farmers preferred using their own farm-saved seeds as opposed to purchasing certified seeds. Establishing the distribution and prevalence of PCN and elucidating the local farming practices that could promote the spread of PCN is a necessary precursor to the implementation of any containment or management strategy in the country and ultimately across the region.

Sammendrag

The invasive slug Arion vulgaris (Gastropoda: Arionidae) is an agricultural pest and serious nuisance in gardens of Central and Northern Europe. To investigate if the success of A.vulgaris in Norway can be attributed to a release from parasites, we compared the prevalence and parasite load of nematodes and trematodes in A. vulgaris to that of three native gastropod species, A. circumscriptus, A. fasciatus and Arianta arbustorum, in SE Norway. We found A. vulgaris to have the highest prevalence of both parasite groups (49% nematodes, 76% trematodes), which does not support the parasite release hypothesis, but rather points to A. vulgaris as a potentially important intermediate host of these parasites. For trematodes the number of individuals (parasite load) did not differ among host species; for nematodes it was higher in A. vulgaris than A. fasciatus. To further compare the parasite susceptibility of the surveyed gastropods, we exposed A. vulgaris, A. fasciatus, and A. arbustorum to a slug parasitic nematode, Phasmarhabditis hermaphrodita, in the laboratory. This nematode is commercially available and widely used to control A. vulgaris. The non-target species A. fasciatus was most affected, with 100% infection, 60% mortality and significant feeding inhibition. A. vulgaris was also 100% infected, but suffered only 20% mortality and little feeding inhibition. The load of P. hermaphrodita in infected specimens was not significantly different for the two Arion species (median: 22.5 and 45, respectively). Only 35% of A. arbustorum snails were infected, none died, and parasite load was very low (median: 2). However, they showed a near complete feeding inhibition at highest nematode dose, and avoided nematode-infested soil. Our results indicate that A. vulgaris may be less susceptible to P. hermaphrodita than the native A. fasciatus, and that non-target effects of applying this nematode in fields and gardens should be further investigated.

Til dokument

Sammendrag

Angiostoma norvegicum n. sp. (Angiostomatidae) is described from the oesophagus, crop and the buccal mass of five species of slugs of the family Arionidae, Arion vulgaris (Moquin-Tandon), Arion ater (L.), Arion fasciatus (Nilsson), Arion fuscus (Müller) and Arion rufus/Arion ater hybrid), collected throughout Norway. Angiostoma norvegicum n. sp. was found parasitising arionids at seven of the 30 sample sites examined (23.3%), and 9.9% of all Arion spp. were infected with this nematode. The new species is characterised by its large size (4.0–8.6 mm long) and in having: lateral alae; 6 + 6 papillae at the cephalic end; a large circular mouth aperture; a spacious stoma; a pharyngeal basal bulb without valvular apparatus; an excretory pore near the base of bulb; a distal part of posterior ovary always outstretched; an anterior ovary distally nearly always outstretched; a vulva situated anterior to mid-body; long, nearly straight spicules and a small gubernaculum; three circumcloacal papillae and caudal genital papillae (GP) arranged in a pattern 1+2/3+3 with GP 5 and GP 8 opened on dorsal side of narrow bursa not reaching tail tip; short conical tails in both sexes with tips supplied by 4 short, unequal denticles. Morphologically, A. norvegicum n. sp. is similar to Angiostoma limacis Dujardin, 1845, which diagnostic characteristics are given based on examination of specimens from Norway and the UK. Conversely, the phylogenetic analyses based on D2D3 large subunit (LSU) rRNA gene sequences performed in the present study did not support the morphological affinity of these two species. Phylogenetic analyses demonstrated that although Angiostoma spp. cluster together, A. norvegicum n. sp. forms a tight monophyletic clade with the milacid nematode parasites Angiostoma margaretae Ross, Malan & Ivanova, 2011 and Angiostoma milacis Ivanova & Wilson, 2009.

Sammendrag

A survey of nematodes associated with terrestrial slugs was conducted for the first time in Norway. A total of 611 terrestrial slugs were collected from 32 sample sites. Slugs were identified by means of morphological examination, dissection of genitalia and molecular analysis using mitochondrial DNA. Twelve slug species were identified, representing four different slug families. Internal nematodes were identified by means of morphological analysis and the sequencing of the 18S rRNA gene. Of the sample sites studied, 62.5% were found to be positive for nematode parasites, with 18.7% of all slugs discovered being infected. Five nematode species were identified in this study: Alloionema appendiculatum, Agfa flexilis, Angiostoma limacis, Angiostoma sp. and Phasmarhabditis hermaphrodita. Of these species, only one nematode was previously undescribed (Angiostoma sp.). This is the first record of the presence of A. appendiculatum, A. flexilis and A. limacis in Norway.

Til dokument

Sammendrag

Snegler er viktige i nedbrytningsprosessen av plantemateriale i naturen. Noen ganske få arter kan opptre som skadedyr på planter i jord- og hagebruk. Områder med høy fuktighet, moderate tempe-raturer og milde vintre utgjør ideelle omgivelser for snegler. Har man i tillegg kulturer som gir sne-glene beskyttelse under et permanent plantedekke, kan skaden av snegl på plantene bli omfattende. Nettkjølsnegl (tidligere kalt åkersnegl) har lenge vært et vanlig skadedyr i mange kulturer i jord- og hagebruk i Norge. Brunskogsnegl (også kalt Iberiaskogsnegl og brunsnegl) er en nykommer i norsk fauna. Foreløpig forekommer denne arten hovedsakelig som skadedyr i småhager, men i enkelte distrikter langs kysten av Sør-Norge har den også opptrådt i dyrka områder. Den har vært rapportert fra mindre grasarealer og som skadegjører hos noen grønnsak- og jordbærprodusenter.

Sammendrag

Snegler er viktige i nedbrytningsprosessen av plantemateriale i naturen. Noen ganske få arter kanopptre som skadedyr på planter i jord- og hagebruk. Områder med høy fuktighet, moderate temperaturer og milde vintre utgjør ideelle omgivelser for snegler. Har man i tillegg kulturer som gir sneglene beskyttelse under et permanent plantedekke, kan skaden av snegl på plantene bli omfattende.Nettkjølsnegl (tidligere kalt åkersnegl) har lenge vært et vanlig skadedyr i mange kulturer i jord- oghagebruk i Norge. Brunskogsnegl (også kalt Iberiaskogsnegl og brunsnegl) er en nykommer i norsk fauna. Foreløpig forekommer denne arten hovedsakelig som skadedyr i småhager, men i enkelte distrikter langs kysten av Sør-Norge har den også opptrådt i dyrka områder. Den har vært rapportert fra mindre grasarealer og som skadegjører hos noen grønnsak- og jordbærprodusenter.

Sammendrag

Det gis en gjennomgang av det forskningsarbeidet som har blitt utført i ulike prosjekter på iberiaskogsnegl siste år. Blant annet diskuteres overvintring og bruk av biologiske og kjemiske midler.

Sammendrag

Oppsummering av resultater fra prosjekt "Kontroll av snutebiller i produksjon av jordbær ved hjelp av planteduftstoffer og andre alternative metoder" (2006-2011).

Sammendrag

Organic fields are often assumed to have less pests and more beneficials than conventionally managed fields. We monitored 12 Norwegian strawberry fields, six organic and six conventional, by sampling leaves two times per year in 2002-2003. Young folded leaflets were visually inspected for eggs and adult females of strawberry mite (Phytonemus pallidus fragariae), and mature leaves were used for extraction of mobile stages of two-spotted spider mite (Tetranychus urticae). The spider mites were examined for infection of the mite-pathogenic fungus Neozygites floridana. Predatory mites (Phytoseiidae) were recorded on both leaf types, and the females mounted and identified. Soil was also sampled from each field, to study the natural occurrence of entomopathogenic nematodes. All samples were taken 0-13 metres from the border vegetation. Both pest mites tended to be more abundant in conventional than in organic fields, while the number of phytoseiid mites was very low in both growing systems. Nevertheless, three phytoseiid species were recorded for the first time in Norway: Amblyseius rademacheri Dosse, Neoseiulus kodryensis (Kolodochka) and Neoseiulus reductus (Wainstein). N. floridana infection found in T. urticae females varied from 0-19%, and was higher in 2002 than in 2003. The fungus was recorded at least once in all 12 fields, and there was no consistent difference between the two growing systems. In 2002 there was a significant negative correlation between % T. urticae with N. floridana hyphal bodies found in the first sampling and the number of T. urticae present in the second sampling about four weeks later. Beneficial nematodes (mostly Steinernema) tended to occur in more of the organic than in the conventional soil samples. To sum up, both pests (T. urticae and P. pallidus) and one of the beneficial groups (entomopathogenic nematodes) seemed to conform to the expected difference between organic and conventional fields. There are many possible mechanisms related to the differences in pesticide and fertilization regimes that could lead to such a pattern. For the two remaining beneficials (N. floridana and Phytoseiidae) we could not find a consistent correlation between abundance and growing system.  

Sammendrag

Haukeland Solveig 1, Kalinga, Yonna 2, Mwatawala Maulid.2 & Maerere Amon.2 1Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Høgskoleveien 7, 1432 Ås, Norway. solveig.haukeland@bioforsk.no 2Sokoine University of Agriculture, Department of Crop Science and Production, P.O. Box 3005 Morogoro, Tanzania. Yonna Kalinga, kalingaye@yahoo.co.uk, Maulid Mwatawala, mwatawala@yahoo.com and Amon Maerere, maerere@yahoo.co.uk Among the most important insect pests in fruit production in Tanzania are fruit flies (Diptera: Tephritidae) these include Bactrocera spp., Ceratitis spp. and Dacus spp. that can significantly reduce yield and fruit quality. Management of fruit flies include cultural control measures such as collecting and destroying infected host fruits, regulatory control (quarantine) and the use of insecticide baits. The best approach for control of fruit flies is to develop an IPM system that include several strategies to reduce the build up of damaging pest populations. Biological control agents such as entomopathogenic nematodes (EPN) are potential candidates within such a system. Naturally occurring EPN isolates in the genera Steinernema and Heterorhabditis have been isolated from a fruit growing area in the Morogoro region in Tanzania. Selected EPN isolates have been tested against larval and pupal stages of three important fruit fly species, Bactrocera invadence, B. cucurbitae and Dacus bivittatus. Results are promising and show that several isolates caused 70% to 90% mortality of larvae for all three fruit fly species. Laboratory studies on the ecological characteristics of selected EPN were also conducted using Galleria mellonella as host.

Sammendrag

Rovmidden Neoseiulus californicus, rovtegen Orius laevigatus og nyttenematoden Heterorhabditis bacteriophora ble brukt til biologisk bekjempelse i Norge inntil 2001, da den nye godkjenningsordningen for nyttedyr trådte i kraft. Godkjenning av disse 3 artene ble avslått fordi man manglet informasjon om forekomst, kuldetoleranse, overvintringsevne og etableringspotensial i Norge. For å skaffe slik informasjon ble en kartlegging av forekomsten av de tre artene Norge startet i 2007, og videreført i 2009. Orius laevigatus og H. bacteriophora ble funnet i kartleggingsundersøkelsen. 2 individer av N. californicus ble funnet på planter på en komposthaug utenfor et veksthus i Trøndelag i 2007. Dette veksthuset har hatt en permanent egen stamme av denne rovmidden. Det ble gjort nærmere undersøkelse utenfor dette veksthuset i 2009, men da ble arten ikke funnet. Det er derfor lite sannsynlig at noen av de 3 artene har etablert seg her i Norge. Det ble også utført overvintringsforsøk med N. californicus og O. laevigatus fra kommersielle nyttedyrpreparater. Forsøkene ble utført på friland på Ås i Akershus fra august 2009 til april 2010. Verken rovmidden eller rovtegene viste tydelige tegn til å gå i diapause utover høsten. Noen få levende rovmidd og rovteger ble funnet i november, men ingen rovmidd eller rovteger overlevde fram til januar. Tidligere overvintrings- og kuldetoleranseforsøk utført på Ås og Lillestrøm med de samme nyttedyrpreparatene viste også lav kuldetoleranse hos N. californicus og O. laevigatus. En vurdering av etableringspotensial i Norge for de to artene er gjort på grunnlag av tilgjengelig informasjon om naturlig utbredelse, diapause, kuldetoleranse og overvintringsevne hos de 2 artene og historisk temperaturdata for Ås og Lier (mildt innlandsklima) og Særheim (mildt kystklima). Per i dag er det lite sannsynlig at N. californicus kan etablere seg permanent i Norge. Det er lite sannsynlig at O. laevigatus kan etablere seg permanent i områder med tilsvarende klima som Ås og Lier, men det er risiko for etablering i områder med tilsvarende klima som Særheim.

Sammendrag

Det gis en oversikt over det siste årets arbeid med iberiaskogsnegl, blant annet utprøving av ulike barrierer for å stoppe sneglene, undersøkelse av overvintring i dyrka områder og videre utprøving av Nemaslug.  Det blir særlig lagt vekt på at arten er i ferd med å invadere noen dyrka områder langs kysten. En må forvente at arten etter hvert blir et viktigere skadedyr i dyrka arealer, særlig i jordbær, grønnsaker og gras.

Sammendrag

The slug parasitic nematode Phasmarhabditis hermaphrodita is commercially available for slug control in many European countries and is mainly used in home gardens against the grey field slug Deroceras reticulatum. It is also used to a certain extent against Arion lusitanicus even though the larger (adult) stages appear to be unaffected. Few studies have examined the efficacy of this nematode on all developmental stages of A. lusitanicus.  Results from on-going studies on the effect of P. hermaphrodita on slug eggs and practical use of P. hermaphrodita will be presented.

Sammendrag

Organic fields are often assumed to have fewer pests and more beneficials than conventionally managed fields. We monitored 12 Norwegian strawberry fields, 6 organic and 6 conventional fields, by sampling leaves twice a year in 2002 and 2003. Young folded leaflets were visually inspected for eggs and adult females of strawberry mite (Phytonemus pallidus fragariae), and mature leaves were used for extraction of mobile stages of two-spotted spider mite (Tetranychus urticae). The spider mites were examined for infection of the mite-pathogenic fungus Neozygites floridana. Predatory mites (Phytoseiidae) were recorded on both leaf types, and the females mounted and identified. We also sampled leaves from selected plants in the boundary vegetation of most fields to look for sources of T. urticae, phytoseiids and N. floridana. Soil was sampled from each field, to study the natural occurrence of entomopathogenic nematodes. All samples were taken 0-13 metres from the border vegetation. Both pest mites tended to be more abundant in conventional than in organic fields, while the number of phytoseiid mites was very low in both growing systems. Nevertheless, three phytoseiid species were recorded for the first time in Norway: Amblyseius rademacheri Dosse, Neoseiulus kodryensis (Kolodochka) and Neoseiulus reductus (Wainstein). N. floridana infection found in T. urticae females varied from 0-19%, and was higher in 2002 than in 2003. The fungus was recorded at least once in all 12 fields, and there was no consistent difference between the two growing systems. In 2002 there was a significant negative correlation between % T. urticae with N. floridana hyphal bodies found in the first sampling and the number of T. urticae present in the second sampling about 4 weeks later. Beneficial nematodes (mostly Steinernema) tended to occur in more of the organic than of the conventional soil samples. To sum up, both pests (T. urticae and P. pallidus) and one of the beneficial groups (entomopathogenic nematodes) seemed to conform to the expected difference between organic and conventional fields. There are many possible mechanisms related to the differences in pesticide and fertilization regimes that could lead to such a pattern. For the two remaining beneficials (N. floridana and Phytoseiidae) we could not find a consistent correlation between abundance and growing system.

Sammendrag

Haukeland Solveig and Sundbye Anette The slug parasitic nematode Phasmarhabditis hermaphrodita is commercially available for slug control in many European countries and is mainly used in home gardens against the grey field slug Deroceras reticulatum. In some European countries it is used against the invasive slug pest Arion lusitanicus. The standard application method for using P. hermaphrodita is by surface application at a rate of 300 000 nematodes per square meter.  Several studies have shown that A. lusitanicus individuals above 1 gram are not affected by P. hermaphrodita and field experiments indicate that this standard application method does not significantly reduce slug populations. Traditional molluscicides include an attractant, often wheat based packed around an active chemical ingredient. A slug baiting method, using P. hermaphrodita as the active ingredient, might be a better approach for biological control of slugs rather than surface application. We therefore decided to test the effect of P. hermaphrodita treated baits in laboratory and field studies. Laboratory experiments suggest this approach as promising, also against slugs above 1 gram. Results from ongoing field experiments will be presented and discussed.  

Til dokument

Sammendrag

Rotsnutebiller kan gi store skadar i jordbær. Larvane lever i jorda og gneg på røter og rotstokk. Billene kan ikkje fl yge, skaden viser seg derfor som fl ekkar i feltet. Svake angrep gir redusert plantevekst med små blad, små bær og lita avling. I enkelte tilfelle kan skaden vere total. Beste mottiltak er korte omløp, vekstskifte og god jordarbeiding. Nyttenematodar kan ha ein viss effekt.

Sammendrag

Mite damage is often considered a spray induced problem. We monitored 12 Norwegian strawberry fields, 6 organic and 6 conventional fields, by sampling leaves two times per year for two years. Young folded leaflets were visually inspected for eggs and adults of strawberry mite (Phytonemus pallidus) and completely unfolded leaves were used for extraction of mobile stages of two-spotted spider mite (Tetranychys urticae). The spider mites were examined for infection of the mite-pathogenic fungus Neozygites floridana. Predatory mites (Phytoseiidae) were recorded on both leaf types, and the females mounted and identified. We also sampled leaves from selected plants in the boundary vegetation of most fields, to look for sources of T. urticae, phytoseiids and N. floridana, and soil from each field, to study the natural occurrence of entomopathogenic nematodes. We will present the results on abundance and diversity of the organisms investigated, and discuss similarities and differences between organic and conventional fields.

Sammendrag

Fra 1. januar 2008 er ingen effektive skadedyrmidler godkjent for bruk mot kålfluer i Norge. Det har siden 2004 vært en stor innsats ved Bioforsk i samarbeid med Landbrukets forsøksringer og med næringen til å finne frem til metoder og midler som vil beskytte korsblomstrede vekster mot kålfluer. Det er spesielt to prosjekter som har støttet mye av dette arbeid, ett brukerstyrt fra kålrotdyrkerne og ett fra Forskningsfondet. Resultatene viser at både nye midler og andre bekjempelsesmetoder kan gi tilfredsstillende beskyttelse. Men det er mye arbeid som gjenstår før all den nye viten kan tas i bruk.

Sammendrag

Rovtegen Orius laevigatus, rovmidden Neoseiulus californicus og nyttenematoden Heterorhabditis bacterophora ble brukt i biologisk bekjempelse i Norge før den nye godkjenningsordningen for nytteorganismer ble innført i 2001. Artene ble ikke godkjent ved vurderingen i 2001 på grunn av uklar systematikk, fare for genetiske innblandinger, usikkerhet rundt naturlig utbredelse og etableringspotensial, og at artene ikke var påvist i Norge. Næringen ønsker å få de 3 artene tilbake på markedet. I vekstsesongen 2007 gjennomførte vi derfor på oppdrag fra Mattilsynet en kartlegging for å undersøke om O. laevigatus, N. californicus og H. bacteriophora har etablert seg i Norge. Vi samlet inn prøver både i områder der artene har vært brukt og i andre områder med mildt klima. Prøvene ble tatt i habitat som så langt det var mulig tilsvarer artenes habitat i det naturlige utbredelsesområdet. Vi fant 91 tegearter, men ikke O. laevigatus. Det ble gjort ett funn av N. californicus på en kompost utenfor et veksthus tidligere har benyttet rovmidden i sin produksjon, og som har mottatt plantemateriale fra en annen produsent har hatt N.californicus i kultur i gartneriet sitt. Dette funnet er ikke tilstrekkelig for å si at rovmidden er etablert i Norge. H. bacteriophora ble ikke funnet. Kuldetoleranseforsøk med 2 populasjoner med ulikt opphav av hver av artene O. laevigatus og N. californicus ble gjennomført i klimaskap ved -12oC, -6,5oC, og 3,0oC (konstant temperatur), og det ble gjort overvintringsforsøk med disse artene på friland i Ås og Lillestrøm i januar-mars 2008. Begge artene døde raskt ved alle de konstante temperaturene. I overvintringsforsøkene ble det funnet overlevende O. laevigatus etter 2 uker, mens N. californicus overlevde i nesten 2 måneder.

Sammendrag

Jorda er bosted for et utallig antall former for planter, dyr og mikrober. Disse varierer fra mikroskopiske encellede organismer til store gravende dyr. Tilsvarende som for overjordiske miljøer, er det godt definerte næringskjeder og konkurranse om overlevelse i jordmiljøet. Ulike samspill i jordøkosystemet kan både fremme og redusere forekomsten av skadedyr (insekter og midd) som er tilknyttet jord. Skadedyr tilknyttet jorda har derfor også naturlige fiender blant jordorganismene, men også skadedyr som bare tilfeldigvis kommer i kontakt med jorda, ved at de for eksempel ramler ned fra planta de lever på, kan bli spist av predatorer ("rovdyr") eller bli infisert av mikroorganismer som finnes på jorda.

Til dokument

Sammendrag

Snegler er viktige i nedbrytningsprosessen av plantemateriale i naturen. Noen ganske få arter kan opptre som skadedyr på planter i jord- og hagebruk. Områder med høy fuktighet, moderate temperaturer og milde vintre utgjør ideelle omgivelser for snegler. Har man i tillegg kulturer som gir sneglene beskyttelse under et permanent plantedekke, kan skaden av snegl på plantene bli omfattende. Åkersnegl har lenge vært et vanlig skadedyr i mange kulturer i jord- og hagebruk i Norge. Iberiaskogsnegl, også kalt brunsnegl, er en nykommer i norsk fauna. Foreløpig forekommer denne arten hovedsakelig som skadedyr i småhager, men i enkelte distrikter langs kysten av Sør-Norge har den også opptrådt i dyrka områder. Den har vært rapportert fra mindre grasarealer og som skadegjører hos noen grønnsakog jordbærprodusenter. På nettsiden snegler.bioforsk.no fi nner du mer informasjon.

Sammendrag

Snegler har vært det store samtaleemnet på Hageselskapets nettprat i sommer. En kjølig og ikke minst fuktig sommer i sør, har ført til at snegleplagen nærmest har eksplodert mange steder i landet. Artikkelen er i form av et intervju av Arild Andertsen og Solveig Haukeland om snegler og deres bekjempelse.

Sammendrag

The large arionid slug Arion lusitanicus is a serious pest in northern Europe including many parts of Norway. In Norway it is mainly a pest in home gardens but in recent years it has also spread to horticultural and vegetable crops such as strawberry and lettuce. The use of the slug parasitic nematode Phasmarhabditis hermaphrodita against A. lusitanicus is being investigated in an ongoing research project that was initiated in 2005. A survey was conducted to examine the natural occurrence of the slug parasitic nematode P. hermaphrodita. The result of the survey was positive which led to registration of the product Nemaslug in 2005. Several experiments have been conducted to study the effect of both the commercial product Nemaslug and Norwegian isolated P. hermaphrodita on A. lusitanicus slugs. Laboratory and controlled pot experiments confirm that young stages of the slug (0.02 - 0.04g) are most susceptible to infection and death. It also appears that soil based bioassays give more consistent results than assays using Petri dishes with filter paper. Further work on the infection process of nematodes in A. lusitanicus slugs as well as the practical aspects of nematode use in gardens and the field are being addressed.

Sammendrag

Gransnutebillen gjør stor skade i granplantninger over hele Europa og kan føre til stort økonomisk tap dersom det ikke settes inn tiltak (Langström & Day, 2004). De voksne billene blir lokket til nye hogstflater av duftene fra hogstavfall og stubber. Billene legger egg i røttene til de ferske stubbene, og larvene utvikler seg i innerbarken. De voksne billene lever lenge og eggleggingen kan skje i to sesonger. Når den nye billegenerasjonen klekker fra stubbene etter 1-2 år begynner de også å ete på de små bartreplantene.

Sammendrag

De fleste av oss har, enten vi har hage, dyrket mark eller ferdes i skog og mark, hatt befatning med iberiaskogsneglen, brunsneglen, mordersneglen, rambosneglen. Mange navn på en etter hvert velkjent skapning i hagene våre. Sneglene tar godt for seg av plantene blomsterbedet, og man kvier seg for å gå barbeint over en duggfrisk villaplen en sen sommerkveld. Salat- og jordbærbøndene har ennå mer å frykte, eller? Foredrag om iberiaskogsnegl levesett og bekjempelse.

Sammendrag

For at en fremmed art skal godkjennes til bruk i biologisk bekjempelse må det gjennomføres grundige studier av bl.a. utbredelse og etableringspotensial i Norge. Rovtegen Orius laevigatus, rovmidden Neoseiulus californicus og nyttenematoden Heterorhabditis bacterophora har vært brukt i biologisk bekjempelse før 2001, da den nye godkjenningsordningen for nytteorganismer ble innført. Artene ble imidlertid ikke godkjent ved vurderingen i 2001. Begrunnelsen var uklar systematikk, fare for genetiske innblandinger, og usikkerhet rundt naturlig utbredelse og etableringspotensial, og at artene ikke var påvist i Norge. Næringen ønsker å få de 3 artene tilbake på markedet. I 2007 gjennomførte vi derfor en kartlegging for å undersøke om O. laevigatus, N. californicus og H. bacteriophora har etablert seg i Norge. Det er samlet inn prøver både i områder der artene har vært brukt og i andre områder med mildt klima. Prøvene ble tatt i habitat som så langt det var mulig tilsvarer artenes habitat i det naturlige utbredelsesområdet. Det ble funnet 91 tegearter, men O. laevigatus ble ikke ble funnet. Det er funnet en del rovmidd, og nyttenematoder. Identifisering av artene vil bli gjort i februar 2008. Kuldetoleranseforsøk med 2 populasjoner fra hver av artene O. laevigatus og N. californicus er startet, og vil avsluttes i mai 2008.

Sammendrag

Occurrence of entomopathogenic nematodes (EPNs) have been reported from all continents in the world except Antarctica. Africa is the continent with fewest reports so far. There have however been reports on EPNs occurrence in Egypt, Kenya and South Africa. EPNs are well known due to their potential as biological control agents of insect pests. Banana weevil (Cosmopolites sordidus) is as an important insect pest of banana. This pest causes reduced banana production in all countries of the East African Highlands in particular Tanzania and Uganda. Different strategies have been employed to control the insect. However the potential for using entomopathogenic nematodes as biological control agents of the weevil has not yet been considered in Tanzania. A preliminary study is ongoing to find out if entomopathogenic nematodes naturally exist in banana growing areas in Tanzania. Currently nine soil samples have been collected from three regions (Mbeya, Morogoro and Coast) with different agroecological conditions. The samples have been taken to Bioforsk in Norway, for extraction of EPNs. Analysis of the samples has been done using larvae of the Greater Wax moth (Galleria mellonella) as bait. After 7 and 14 days dead larvae were removed from the soil samples and placed on water agar. Some of the dead larvae were infected with entomopathogenic fungi and at least one sample had a dead larva with EPN infection. In this sample an adult nematode in the genus Steinernema was isolated. Many dead larvae also had what appeared to be secondary infections of saprophytic nematodes (Rhabditidae) and/or saprophytic fungi. Identification to species or genus level of the nematodes is ongoing. This study reports the find of EPNs for the first time in Tanzania. The isolation of indigenous EPNs are important for further studies on their suitability for control of local insect pests including banana weevils. Future work will include more soil samples for EPNs analysis and semi-field tests using EPNs against banana weevil.

Sammendrag

Occurrence of entomopathogenic nematodes (Epn) have been reported from all continents in the world except Antarctica. Africa is the continent with fewest reports so far. There have however been reports on Epn occurrence in Egypt, Kenya and South Africa. Epns are well known due to their potential as biological control agents of insect pests. Banana weevil (Cosmopolites sordidus) is considered as an important insect pest of banana. This pest causes reduced banana production in all countries of the East African Highlands in particular Tanzania and Uganda. Different strategies have been employed to control the insect. However the potential for using entomopathogenic nematodes as biological control agents of the weevil has not yet been considered in Tanzania. A preliminary study is ongoing to find out if entomopathogenic nematodes naturally exist in banana growing areas in Tanzania. Currently nine soil samples have been collected from three regions (Mbeya, Morogoro and Coast) with different ecological conditions. The samples have been taken to Bioforsk in Norway, for extraction of Epn. Analysis of the samples has been done using larvae of the Greater Wax moth (Galleria mellonella) as bait. After 7 and 14 days dead larvae were removed from the soil samples and placed on water agar. Some of the dead larvae were infected with entomopathogenic fungi and at least one sample had a dead larva with Epn infection. In this sample an adult nematode in the genus Steinernema was isolated. Many dead larvae also had what appeared to be secondary infections of saprophytic nematodes (Rhabditidae) and/or saprophytic fungi. Identification to species or genus level of the nematodes is ongoing. This study reports the find of Epn for the first time in Tanzania. The isolation of indigenous Epns are important for further studies on their suitability for control of local insect pests including banana weevils. Future work will include more soil samples for Epn analysis and semi-field tests using Epn against banana weevil.

Sammendrag

Fra tid til annen gulner plenen og andre grøntarealer uten at noen synlig grunn foreligger. Årsaken til gulningen kan være oldenborrelarver. Artikkelen beskriver problemet med oldenborrer i plen og om bekjempelse.

Sammendrag

Entomopathogenic nematodes (EPNs) are commercially available for control of soil dwelling larvae of the vine weevil (Otiorhynchus sulcatus). In Europe several products are available comprising three different species, Heterorhabditis bacteriophora, H. megidis, and Steinernema kraussei. The latter species is for use at low temperatures. Results from several trials using H. megidis and S. kraussei against vine weevil in strawberry fields indicate that low temperature, soil type and possibly the application method are limiting factors that appear to reduce their efficacy. The use of EPNs against vine weevil larvae in the field will be discussed including results from cold-activity studies and application methods.

Sammendrag

Different methods to reduce the population of Arion lusitanicus are being investigated in private gardens naturally infested with the slug. In the laboratory the effect of different mulches are also being tested. Preliminary results from the studies conducted in gardens indicate that physical removal of slugs by picking or trapping and killing is most effective. In arenas in the laboratory, slugs avoided cocoa chips mulch and alginate granules. These studies are on-going and will be completed at the end of 2008. The slug parasitic nematode Phasmarhabditis hermaphrodita has recently been isolated in Norway. It is being studied as a biological control agent of A. lusitanicus. Results so far show that young slugs (0,02 " 0,04g) are most susceptible to infection and death. It also appeared that soil based bioassays gave better and more consistent results than assays using Petri dishes with filter paper. Further studies on the host-parasitic relationship of the nematode and slug are required.

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

The large arionid slug Arion lusitanicus is a serious pest in parts of northern Europe including many parts of Norway. In Norway it has mainly been a pest in home gardens but in recent years it has also spread to horticultural and vegetable crops such as strawberry and lettuce. The use of the nematode Phasmarhabditis hermaphrodita against A. lusitanicus is being investigated in an on-going research project that was initiated in 2005. A survey was conducted in 2004 to examine if the nematode P. hermaphrodita could be found occurring naturally in Norway. The result of the survey was positive which led to registration of the product Nemaslug in 2005. Several experiments have been carried out since 2005, to study the effect of both the commercial product Nemaslug and Norwegian isolated P. hermaphrodita on A. lusitanicus slugs. Laboratory and controlled pot experiments confirm that young stages of the slugs are susceptible to the slug parasitic nematode. Further work on the infection process of nematodes in slugs as well as the practical aspects of nematode use in gardens and the field will be addressed as a next step in these studies.

Sammendrag

The presence of Steinernema carpocapsae is reported for the first time in a Nordic country. Entomopathogenic nematodes were isolated from soil in apple orchards in Western Norway. Nematodes in the genus Steinernema were present in 11.9% of the samples including a population of S. carpocapsae. According to our knowledge the presence of S. carpocapsae is rare in northern Europe, and a report several years ago of this species from northern Sweden appears to have been S. feltiae not S. carpocapsae. This paper also presents an overview of entomopathogenic nematodes in the Nordic countries where the following species are reported: S. affine; S. bicornotum; S. carpocapsae; S. feltiae; S. intermedium; S. kraussei; S. silvaticum; `Steinernema sp. C1", `Steinernema sp. E"; Heterorhabditis downesii and H. megidis. The occurrence of entomopathogenic nematodes in the Nordic countries is based on area-wide surveys for some of the countries.

Sammendrag

Alternative metoder for å begrense skader forårsaket av gransnutebillen er svært aktuelle, både av hensyn til miljøet og fordi dagens kjemiske midler er på vei ut av bruk. I denne artikkelen fokusere vi på muligheten for å bruke et biologisk middel, nyttenematoder. Strategien med bruk av nyttenematoder går ut på å redusere produksjonen av nye gransnutebiller ved å drepe så mange larver som mulig i stubbene hvor de lever.

Sammendrag

The black vine weevil (Otiorhynchus sulcatus) is an important pest in many crops in several countries worldwide. The adults feed on the leaves of strawberries, rhododendrons, azaleas and many other ornamental plants. Indoors, O. sulcatus can infest begonias, ferns, cyclamins, and other common container plants. Adult feeding does not seriously affect the plants, it is the larval feeding on roots of host plants that causes the most serious plant injury. Larvae may also girdle the main stem below the soil line. Leaves will yellow and plants may be stunted or die. O. sulcatus weevils are difficult to control once established because of their nocturnal behaviour and the subterranean habits of the larvae. In strawberries chemical control using a pesticide against the adult weevils after harvest is the most common control method today, however the most effective pesticides will shortly no longer be available and there are few alternative pesticides on the market. Fortunately there are Entomopathogenic nematodes (EPN) that can be used to control the soil dwelling larvae and in Europe there are several products on the market comprising three species (Heterorhabditis bacteriophora, H. megidis, and Steinernema kraussei). The use of these nematodes has shown to be quite successful in potted plants (in nurseries), whereas in field grown crops such as strawberry they are still not consistently effective. In this presentation results from a number of field trials using H. megidis and S. kraussei against O. sulcatus larvae infesting field grown strawberry will be presented and discussed.

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

The use of entomopathogenic nematodes against the vine weevil Otiorynchus sulcatus was studied under field conditions. A number of field trials were conducted using two commercial products of EPN, Nemasys H (Heterorhabditis megidis) and Nemasys L (Steinernema kraussei). The results from these trials indicate that low temperature is still a limiting factor for the successful use of EPN against O. sulcatus in Northern Europe. Furthermore it was observed that application methods of EPN in field grown strawberries requires improvement.

Sammendrag

The large arionid slug Arion lusitanicus is a serious pest in parts of northern Europe including many parts of Norway. In Norway it has mainly been a pest in home gardens but in recent years it has also spread to horticultural and vegetable crops such as strawberry and lettuce. This latter aspect is of great concern and a research project was initiated in 2005 to study the biology and control of this pest. The main aim of the project is to develop direct and preventive measures to reduce damage and further spread of the slug. To achieve this aim, the life-cycle, population dynamics and over-wintering strategies needs to be determined, as well as the distribution of the slug in the country. Direct and preventive measures are studied in gardens, in crops and in more controlled conditions. The studies include the use of biological agents such as the slug-parasitic nematode Phasmarhabditis hermaphrodita

Til dokument

Sammendrag

Sneglene er viktige i nedbrytningsprosessen av plantemateriale i naturen. Noen ganske få arter kan opptre som skadedyr på planter i jord- og hagebruk. Områder med høy fuktighet, moderate temperaturer og milde vintre utgjør ideelle omgivelser for snegler. Har man i tillegg kulturer som gir sneglene beskyttelse under et permanent plantedekke, kan skaden av snegl på plantene bli omfattende. Åkersnegl har lenge vært et vanlig skadedyr i mange kulturer i jord- og hagebruk i Norge. Iberiaskogsnegl, også kalt brunsnegl, er en nykommer i norsk fauna. Foreløpig forekommer denne arten hovedsakelig som skadedyr i småhager, men i enkelte distrikter langs kysten av Sør-Norge har den opptrådt i store mengder. Den har vært rapportert fra mindre grasarealer og som skadegjører hos noen grønnsaks- og jordbærprodusenter.

Sammendrag

Snegler er mange hageeiers store fortvilelse. Har du først fått brunsnegl (iberiaskogsneglen) i hagen, spiser den det meste. Foreløpig er det ikke mulig å utrydde den, men starter du sneglekrigen tidlig er det mulig å begrense antallet.

Sammendrag

In Scandinavia studies on entomopathogenic nematodes (epn) began in Denmark more than 70 years ago and two new species in the genus Steinernema were described (Bovien 1937). In Sweden, a few decades later, Pye and Burman (1978) studied the use of Steinernema spp. against the large pine weevil (Hylobius abietis) in forestry for the first time. Today the use of epn in Scandinavia is, like most countries, most successful and most commonly employed in protected environments such as glasshouses. Use outdoors is mostly in strawberries or in nurseries against root weevils (Otiorhynchus spp.) but in general the use outdoors is still rather limited. The potential for using epn in forestry against the large pine weevil (H. abietis) has not yet been realized. For Sweden with its large forested areas it may be difficult to use epn due to immigration of the pest from surrounding forests. The use of epn in smaller Norwegian forests may be more feasible where immigration of the pest may be less of a problem. The use of epn in a slow release system (`Nemabag") against pests, such as the pollen beetle and flea beetle (Meligethes aeneus and Phyllotreta spp.) in arable crops, has been studied in Finland. Use of epn in private gardens has not been monitored, but there appears to be great interest in using epn to control grubs such as the garden chafer (Phyllopertha horticola), which is an increasing problem in many countries. In Denmark Heterorhabditis bacteriophora has been tested, not always successfully, against P. horticola on golf courses. Another beneficial nematode, pathogenic to slugs, Phasmarhabditis hermaphrodita is also on the market in some of the countries for use against the important slug pests Deroceras reticulatum and Arion lusitanicus. The latter species is becoming increasingly important as a pest not only in private gardens but also in cultivated crops such as strawberries.

Sammendrag

Entomopathogenic nematodes (EPN) are used for biological control of the soil dwelling stages of the vine weevil, Otiorhynchus sulcatus, a serious pest of ornamentals and field grown strawberries. Several nematode species such as Heterorhabditis megidis, H. bacteriophora and Steinernema kraussei are commercially available in Europe for control of the vine weevil. S. kraussei is sold as a cold active strain for use outdoors at low temperatures. In southern Norway, several field trials have been conducted to examine the effect of S. kraussei on vine weevil larvae at low temperatures. The trials were assessed one month after nematode treatments and showed rather poor effect at soil temperatures below 12oC. Further work is necessary to investigate the long-term effect of the applied nematodes as well as biotic and abiotic factors that may affect nematode efficacy.

Sammendrag

Entomopathogenic nematodes (EPN) are used for biological control of the soil dwelling stages of the vine weevil, Otiorhynchus sulcatus, a serious pest of ornamentals and field grown strawberries. The nematodes Heterorhabditis megidis, H. bacteriophora and Steinernema kraussei are commercially available in Europe for control of the vine weevil. S. kraussei is sold as a cold active strain for use outdoors at low temperatures. In southern Norway, several field trials were conducted in strawberries to examine the effect of S. kraussei on vine weevil larvae at low temperatures. The trials were assessed one month after nematode treatments and showed rather poor effect at soil temperatures below 12oC. Further work is necessary to investigate the long-term effect of the applied nematodes as well as biotic and abiotic factors that may affect nematode efficacy. For comparison, the nematode H. megidis was used in these same trials and the results showed that this species is effective at soil temperatures above 12oC, there was no indication that H. megidis had any effect at low temperatures.

Sammendrag

I 2004 og 2005 ble det utført en del feltforsøk for å undersøke effekten av to kommersielle preparater av nyttenematoder, Nemasys H og Nemsays L, mot larver av veksthussnutebillen. Resultatene viser at Nemasys H har ingen eller svært dårlig virkning når gjennomsnittstemperaturen i jorda (5-10 cm dybde) faller under 12 grader. For Nemasys L var virkningen ved slik lav temperatur noe bedre, men ikke så god som forventet. Langtidsvirkningen av nematodeutslippetne er ikke undersøkt, men basert på erfaringer fra feltforsøk utført hittil anbefales det å behandle med Nemasys H om høsten eller tidlig på våren når jordtemperaturen er 12 grader eller mer.

Sammendrag

Sammendrag av foredrag som ble holdt på engelsk på et COST-møte om nyttenematoder i Italia i juni 2005. Foredraget tok for seg biologien til jordbærsnutebille og bringebærbille og så på mulighetene for å bekjempe dem med nematoder. Se engelsk versjon for mer informasjon

Sammendrag

Artikkelen oppsummerer noen små forsøk som er gjort på biologi, overvåking og skade, samt med nye kjemiske midler, nyttenematoder og utgjerding i årene 2000-2003.  Enkelte populasjoner av jordbærsnutebille ser ikke lenger ut til å la seg bekjempe med konvensjonelle plantevernmidler. Utenlandske forsøk har vist at jordbærplanter kan kompensere for opptil 50% avbitte knopper ved å utvikle nye knopper og/eller øke bærstr, men dette ser i liten grad ut til å gjelde norske jordbærplanter. I et økologisk felt som ble fulgt i 4 år, økte antall avbitte knopper per plante sterkt fra første til tredje høstingsår, for så å avta. I det tredje året var oppimot 80 blomsterknopper avbitt per plante. For å overvåke billebestanden i et felt, er registrering av selve billen ved risitng av planter over et hvitt fat en raskere metode enn å telle avbitte knopper, og sier også mer om mulig framtidig skade. Pilotforsøk med utgjerding og nyttenematoder har vist lovende resultater.

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

Planteforsk Plantevernet får mange henvendelser om skade på plen som skyldes hageoldenborre Phyllopertha horticola. Artikkelen tar for seg biologisk bekjempelse av disse skadegjørerne med nematoden Heterorabditis megidis. Det er også en kort beskrivelse om hageoldenborrenes biologi.

Sammendrag

Artikkelen omhandler spesielt regulering og risikovurdering for bruk av nyttenematoder i biologisk bekjempelse av skadedyr.

Sammendrag

I Norge har vi to viktige arter bladnematoder som skader jordbær: Aphelenchoides fragariae og A. blastophthorus. Sistnevnte forekommer naturlig på en rekke ugrasarter, og er særlig godt utbredt på Vestlandet og i Nord-Norge. Den fremstår som et unikt norsk problem og i juni 1996 ble det startet et prosjekt for å finne tiltak mot nematoden. Artikkelen beskriver biologi og symptomer, overlevelse og smitte, forebyggende tiltak, retningslinjer for innsending av prøver og aktuell litteratur.

Sammendrag

Jordprøver ble samlet inn fra ett økologisk og ett konvensjonelt jordbærfelt, fra hver av 6 lo-kaliteter i Norge (Lier, Follo, Evje, Finnskog, Kise, Toten). Prøvetakingen ble foretatt i sep-tember/oktober 2002. Det er foreløpig påvist insektpatogene nematoder i slekten Steinernema i 3 av lokalitetene. Nematodene som er isolert oppformeres og vil bli artsidentifisert og un-dersøkt nærmere til bruk mot rotsnutebiller. I et laboratorieforsøk er to norske nematodearter testet ved to temperaturer mot larver av rotsnutebiller, sammenlignet med det kommersielle produktet Nemasys H. Fra dette prelimi-nære forsøket ble det etter to ukers inkubasjon observert mortalitet av larvene ved 6oC for en av de norske artene, og en noe lavere mortalitet for larver behandlet med Nemasys H.

Sammendrag

Steinernema feltiae er bruk til bekjempelse av hærmygg (Bradysia paupera) på prydplanter, f.eks. julestjerne i veksthus.  Hos julestjerneprodusenter er det registrert dårlig virkning av S. feltiae ved høye temperaturer rundt 30 grader eller mer.  I denne artikkelen beskrives et forsøk der overlevelse av S. feltiae i torvbrikketer (Jiffy-7) med stikklinger av julestjerne.  Temperaturene som ble tested var 24, 30 og 35 grader der overlevelse (antall nematoder per torvbrikkett) ble registrert etter 4, 10 og 21 dager.  Ved alle temperaturene ble det registrert redusert overlevelse over tid.  Det ble ikke registrert signifikant dårligere overlevelse ved 30 eller 35 grader.

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

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

Angrep av rotsnutebillelarver kan være et problem særlig der jordbær dyrkes på plast på lettere jordarter. Bare angrep av få larver kan gi økonomisk skade. Tradisjonelt er bekjempelse gjort med kjemiske midler, men effektiviteten har vært for dårlig slik at angrep av rotsnutebiller i feltene har vært katastrofalt. Nå er en ny og oppsiktsvekkende biologisk bekjempingsmetode under utprøving som et samarbeid mellom Planteforsk Plantevernet og prosjektet "Miljøvennlig kvalitetsproduksjon av jordbær" i Midt-Agder Forsøksring. I utprøvingen blir det brukt nyttenematoder som selv søker etter rotsnutebillelarvene og dreper dem. Resultatene hittil er meget lovende.

Sammendrag

Skade- og nyttedyr i frukthagar, deira kroppsbygnad, struktur og funksjon, utvikling og skade. Bestemmingsnøklar. Plantesjukdommar. Skade- og mangelsymptom. Norsk tekst til 72 fargeplansjar