Biografi

Jeg leder Avdeling skadedyr og ugras i skog-, jord- og hagebruk og har 20 års erfaring som prosjektleder og  13 år som leder av avdelinger/ seksjoner ved NIBIO. Min forskningsvisjon er å utvikle fremtidens “best of” Integrerte Plantevern som vil føre til en bærekraftig matproduksjon gjennom en effektiv bekjempelse av skadegjørere og minimal bruk av syntetiske plantevernmidler.

Mine mål er derfor å:

  1. Utvikle kunnskap om samspill mellom planter, skade- og nytteorganismer som kan brukes i nye og innovative plantevernstrategier
  2. Utvikle nye og effektive biokontroll verktøy
  3. Kombinere  ny teknologi med biologisk kontroll for mer presise, effektive og økonomisk bærekraftige plantevernstrategier
  4. Formidle kunnskap til næring, forvaltning  og allmennheten som vil være med på å fremme bruken og tilgangen til biologiske kontrollmetoder som viktige verktøy i Integrert Plantevern.

Hovedfokuset for min forskning er integrert plantevern og biologisk bekjempelse av skadedyr. Mitt spesialfelt er insektpatologi og samspillet mellom insekt- og middpatogene sopp med planter skade- og nyttedyr og hvordan dette kan brukes i mikrobiologisk bekjempelse av skadedyr. Jeg jobber med begge hovedgruppene av insekt- og middpatogene sopp som hører til Putesoppene (Hypocreales) og Insektmuggsoppene (Entomophtoromycota).

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Pandora neoaphidis is a common entomopathogenic fungus on Sitobion avenae, which is an important aphid pest on cereals in Europe. Pandora neoaphidis is known to cause epizootics (i.e. an unusually high prevalence of infected hosts) and the rapid collapse of aphid populations. We developed a weather-driven mechanistic model of the winter wheat-S. avenae-P. neoaphidis system to simulate the dynamics from spring to harvest. Aphid immigration was fixed at a rate that would lead to a pest outbreak, if not controlled by the fungus. We estimated the biocontrol efficacy by running pair-wise simulations, one with and one without the fungus. Uncertainty in model parameters and variation in weather was included, resulting in a range of simulation outcomes, and a global sensitivity analysis was performed. We identified two key understudied parameters that require more extensive experimental data collection to better assess the fungus biocontrol, namely the fungus transmission efficiency and the decay of cadaver, which defines the time window for possible disease transmission. The parameters with the largest influence on the improvement in yield were the weather, the lethal time of exposed aphids, the fungus transmission efficiency, and the humidity threshold for fungus development, while the fungus inoculum in the chosen range (between 10 and 70% of immigrant aphids carrying the fungus) was less influential. The model suggests that epizootics occurring early, around Zadoks growth stage (GS) 61, would lead to successful biocontrol, while later epizootics (GS 73) were a necessary but insufficient condition for success. These model predictions were based on the prevalence of cadavers only, not of exposed (i.e. infected but yet non-symptomatic) aphids, which in practice would be costly to monitor. The model suggests that practical Integrated Pest Management could thus benefit from including the cadavers prevalence in a monitoring program. We argue for further research to experimentally estimate these cadaver thresholds.

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Rapporten inneholder ei sammenstilling av kunnskap om status for miljømessig, økonomisk og sosial bærekraft i norsk jordbruksproduksjon og er svar på et oppdrag som NIBIO fikk fra Landbruks- og matdepartementet i november 2022. Bærekraft er operasjonalisert som jordbrukets evne til å vedvare. Det bestemmes igjen av om det drives på en måte som ikke kommer i konflikt med seg sjøl og sitt eget produksjonsgrunnlag og heller ikke med livsvilkår og ressurser for mennesker og hensyn til naturmiljøet utenfor sektoren. Det er også forutsatt at norsk jordbruk skal levere goder og tjenester i tråd med mål fastlagt i norsk landbrukspolitikk. Dette betyr ikke at konservering av status er et mål. Det kan tvert imot være slik at endringer nettopp er en avgjørende forutsetning for at jordbruket i Norge kan bestå og levere godt i all framtid. Dette skal analyseres i en etterfølgende del 2 av oppdraget. Hovedpunkt fra gjennomgangen av kunnskapskilder og ei sluttvurdering av status for bærekraft finnes i et sammendrag sist i rapporten.

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In Scandinavia, the bird cherry-oat aphid Rhopalosiphum padi overwinter as eggs on the bird cherry tree Prunus padus. Branches of P. padus were collected at the late February / early March from 17 locations in Norway over a three-year period. We found 3599 overwintering aphid eggs, 59.5% of which were dead. Further, a total of 879 overwintering fungus-killed cadavers were observed. These cadavers were found close to bud axils, where overwintering eggs were also usually attached. Cadavers were infected with either Zoophthora cf. aphidis or Entomophthora planchoniana. All the fungal-killed cadavers were filled with overwintering structures of Z. cf. aphidis (as resting spores) or E. planchoniana (as modified hyphal bodies). We found a significant negative correlation between eggs and cadavers per branch. However, both numbers of eggs and cadavers varied greatly between years and among tree locations. This is the first report of E. planchoniana overwintering in R. padi cadavers as modified hyphal bodies. We discuss whether P. padus may act as an inoculum reservoir for fungi infecting aphids in cereals in spring.

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Her presenteres resultater fra en undersøkelse av forekomst av miljøgifter/ plantevernmidler ekstrahert fra insekter samlet i Malaisefeller i den løpende nasjonale insektovervåkingen. Undersøkelsen er gjennomført av NIBIO på oppdrag fra Miljødirektoratet via det NINA-koordinerte prosjektet Hotspots for trua arter på land: kartlegging med digitale verktøy. Vi har fokusert på kjemiske syntetiske plantevernmidler som brukes i jord- og hagebruk for å belyse problematikk knyttet til funn av miljøgifter i oppsamlingsvæsken i et utvalg av insektfellene. Det er videre gjort en vurdering av hvordan en overvåking som skal si noe om plantevernmidlers påvirkning på insektforekomst (og diversitet) bør utformes. For fullt sammendrag se side 4.

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Cattle production is constantly threatened by diseases like East Coast fever, also known as theileriosis, caused by the protozoan parasite Theileria parva which is transmitted by ticks such as the brown ear tick, Rhipicephalus appendiculatus. To reduce the extensive use of chemical acaricides, fungal-based microbial control agents such as Metarhizium anisopliae have been tested and show promising results against R. appendiculatus both in field and in semi-field experiments in Africa. However, no known endeavors to link the spatial distribution of R. appendiculatus to climatic variables important for the successful application of M. anisopliae in selected East African countries exists. This work therefore aims to improve the successful application of M. anisopliae against R. appendiculatus by designing a temperature-dependent model for the efficacy of M. anisopliae against three developmental stages (larvae, nymphs, adults) of R. appendiculatus. Afterward a spatial prediction of potential areas where this entomopathogenic fungus might cause a significant epizootic in R. appendiculatus population in three selected countries (Kenya, Tanzania, Uganda) in Eastern Africa were generated. This can help to determine whether the temperature and rainfall at a local or regional scale might give good conditions for application of M. anisopliae and successful microbial control of R. appendiculatus.

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Despite substantial efforts to control locusts they remain periodically a major burden in Africa, causing severe yield loss and hence loss of food and income. Distribution maps indicating the value of the basic reproduction number R0 was used to identify areas where an insect pest can be controlled by a natural enemy. A dynamic process-based mathematical model integrating essential features of a natural enemy and its interaction with the pest is used to generate R0 risk maps for insect pest outbreaks, using desert locust and the entomopathogenic fungus Metarhizium acridum (Synn. Metarhizium anisoliae var. acridum) as a case study. This approach provides a tool for evaluating the impact of climatic variables such as temperature and relative humidity and mapping spatial variability on the efficacy of M. acridum as a biocontrol agent against desert locust invasion in Africa. Applications of M. acridum against desert locust in a few selected African countries including Morocco, Kenya, Mali, and Mauritania through monthly spatial projection of R0 maps for the prevailing climatic condition are illustrated. By combining mathematical modeling with a geographic information system in a spatiotemporal projection as we do in this study, the field implementation of microbial control against locust in an integrated pest management system may be improved. Finally, the practical utility of this model provides insights that may improve the timing of pesticide application in a selected area where efficacy is highly expected.

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The genus Metarhizium is composed of species used in biological control programs of agricultural pests worldwide. This genus includes common fungal pathogen of many insects and mites and endophytes that can increase plant growth. Metarhizium humberi was recently described as a new species. This species is highly virulent against some insect pests and promotes growth in sugarcane, strawberry, and soybean crops. In this study, we sequenced the genome of M. humberi, isolate ESALQ1638, and performed a functional analysis to determine its genomic signatures and highlight the genes and biological processes associated with its lifestyle. The genome annotation predicted 10633 genes in M. humberi, of which 92.0% are assigned putative functions, and ∼17% of the genome was annotated as repetitive sequences. We found that 18.5% of the M. humberi genome is similar to experimentally validated proteins associated with pathogen–host interaction. Compared to the genomes of eight Metarhizium species, the M. humberi ESALQ1638 genome revealed some unique traits that stood out, e.g., more genes functionally annotated as polyketide synthases (PKSs), overrepresended GO-terms associated to transport of ions, organic and amino acid, a higher percentage of repetitive elements, and higher levels of RIP-induced point mutations. The M. humberi genome will serve as a resource for promoting studies on genome structure and evolution that can contribute to research on biological control and plant biostimulation. Thus, the genomic data supported the broad host range of this species within the generalist PARB clade and suggested that M. humberi ESALQ1638 might be particularly good at producing secondary metabolites and might be more efficient in transporting amino acids and organic compounds.

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Simple Summary The bird cherry-oat aphid and the fungal plant pathogen causing stagonospora nodorum blotch (SNB) are common pests of wheat. Plants are under constant attack by multiple pests and diseases but there are limited studies on the interaction between several pests on wheat. We therefore conducted controlled greenhouse and laboratory experiments to determine how these pests affected each other on a wheat plant. We found that aphid feeding predisposed wheat to fungal disease, but that aphids preferred and reproduced better on leaves that had not been infected by the fungal pathogen. These results are important to understand the interactions between multiple pests on wheat and how to develop new control strategies in future integrated pest management (IPM). Abstract Wheat plants are under constant attack by multiple pests and diseases. Until now, there are no studies on the interaction between the aphid Rhopalosiphum padi and the plant pathogenic fungus Parastagonospora nodorum causal agent of septoria nodorum blotch (SNB) on wheat. Controlled experiments were conducted to determine: (i) The preference and reproduction of aphids on P. nodorum inoculated and non-inoculated wheat plants and (ii) the effect of prior aphid infestation of wheat plants on SNB development. The preference and reproduction of aphids was determined by releasing female aphids on P. nodorum inoculated (SNB+) and non-inoculated (SNB−) wheat leaves. The effect of prior aphid infestation of wheat plants on SNB development was determined by inoculating P. nodorum on aphid-infested (Aphid+) and aphid free (Aphid−) wheat plants. Higher numbers of aphids moved to and settled on the healthy (SNB−) leaves than inoculated (SNB+) leaves, and reproduction was significantly higher on SNB− leaves than on SNB+ leaves. Aphid infestation of wheat plants predisposed the plants to P. nodorum infection and colonization. These results are important to understand the interactions between multiple pests in wheat and hence how to develop new strategies in future integrated pest management (IPM).

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Simple Summary Sugarcane, an important cash crop in Malawi, is susceptible to numerous insect pests, and many farmers rely heavily on chemical insecticides for their control. Biopesticides containing insect pathogens are used in several countries outside Malawi; however, the occurrence and use of insect pathogens is limited in Malawi. In this study, we evaluated the natural occurrence of insect pathogenic fungi in sugarcane (Saccharum officinarum) and in soil samples from sugarcane fields in Chikwawa District, southern Malawi. Insect pathogenic fungi from soil were isolated by baiting using larvae of the greater wax moth (Galleria mellonella). Insect pathogenic fungi were also isolated from surface-sterilized sugarcane leaves, stems, and roots. We found three types of insect pathogenic fungi: Beauveria bassiana, Metarhizium spp., and Isaria spp. Beauveria bassiana and Isaria spp. were found mostly from sugarcane leaves and stems, while Metarhizium spp. was mainly found in soils. To the best of our knowledge, this is the first report of B. bassiana and Isaria spp. occurring naturally as endophytes in sugarcane. Further, it is the first report of B. bassiana, Isaria spp. and Metarhizium spp. in the soil of sugarcane fields in Africa. Abstract The natural occurrence of entomopathogenic fungal endophytes in sugarcane (Saccharum officinarum) and in soil samples from sugarcane fields was evaluated in Chikwawa District, southern Malawi. Fungi from soil were isolated by baiting using Galleria mellonella larva. Fungal endophytes were isolated from surface-sterilized plant tissue sections. Forty-seven isolates resembled the genus Beauveria, 9 isolates were Metarhizium, and 20 isolates were Isaria. There was no significant difference in the number and type of fungal isolates collected from soil and from plant tissue. There was, however, a significant difference in the part of the plant where fungal species were isolated, which fungal species were isolated, and the number of fungal species isolated at each location. Phylogenetic analysis of 47 Beauveria isolates based on DNA sequencing of the Bloc intergenic region indicated that these isolates all belonged to B. bassiana and aligned with sequences of B. bassiana isolates of African and Neotropical origin. The Malawian B. bassiana isolates formed a distinct clade. No larvae died from infestation by multiple fungi. To the best of our knowledge, this is the first report of B. bassiana and Isaria spp. occurring naturally as endophytes in sugarcane. Further, it is the first report of B. bassiana, Isaria spp., and Metarhizium spp. in the soil of sugarcane fields in Africa.

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The EU has developed a Directive on Sustainable Use of Chemical Pesticides (2009/128/EC) (SUD) that aims to enhance the use of non-chemical alternatives to pesticides like microbial plant protection products (PPP). The number of authorized microbial PPP for plant protection has increased globally during the last decade. There is, however, variation between different countries. Sweden and Denmark have for example each authorized 20 microbial PPP while Norway has only authorized four microbial PPP. Norway has also received significantly fewer applications for authorization of microbial PPP than the other Scandinavian countries. We explore possible explanations for the observed differences. Our results show that that the regulations in the three countries had similar requirements for the authorisation of microbial PPP. The size of the market is somewhat smaller in Norway than in Sweden and Denmark, and could therefore explain some of the differences. We suggest, however, that the most important explanation is implementation differences in terms of different decisions made in the authorization process. By comparing the authorization process for three microbial PPP in the Scandinavian countries, we found that Norway used more time for the product authorization decisions. Norway assess the same types of microbial PPP more restrictively with respect to environmental aspects and especially human health risks.

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In Norway, strawberry producers use cereal straw mulching to prevent berries from contacting the soil and to control weeds. We hypothesized that organic matter such as straw mulch also favors the maintenance of predatory mites which visit strawberry plants at nighttime. We compared mite diversity in cereal straw exposed for different periods in strawberry fields and evaluated their possible migration to plants in two experiments with potted plants in 2019. An ‘Early season’ experiment compared no mulching (T1), oat straw mulch exposed in field since 2018 (T2), or 2017 (T3), while a ‘Mid-season’ experiment compared no mulching (T1), barley straw mulch from 2018 (T2), or a mix from 2017 and 2018 (T3). To provide edaphic predatory mites with a potential source of food, all plants were infested with two-spotted spider mite (Tetranychus urticae Koch). Results suggested that straw mulch facilitates the prevalence of predatory mites in strawberry fields. Most predatory mite visits were at night, confirming our initial hypothesis. Predominant nocturnal mites on leaves belonged to Melicharidae (Proctolaelaps sp.) (‘Early season’, T2), Blattisociidae (Lasioseius sp.) (‘Early and Mid-season’, T3) and Phytoseiidae (‘Mid-season’, T2). Parasitus consanguineus Oudemans & Voigts was the predominant species (‘Early season’, T3) at the base of plants. Anystidae were diurnal visitors only (‘Mid-season’, T2). Future studies should evaluate the predation potential of Proctolaelaps sp. and Lasioseius sp. on two-spotted spider mite and other strawberry pests.

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Invasive alien species and new plant pests are introduced into new regions at an accelerating rate, due to increasing international trade with soil, plants and plant products. Exotic, plant pathogenic oomycetes in soil from the root zone of imported plants pose a great threat to endemic ecosystems and horticultural production. Detecting them via baiting and isolation, with subsequent identification of the isolated cultures by Sanger sequencing, is labour intensive and may introduce bias due to the selective baiting process. We used metabarcoding to detect and identify oomycetes present in soil samples from imported plants from six different countries. We compared metabarcoding directly from soil both before and after baiting to a traditional approach using Sanger-based barcoding of cultures after baiting. For this, we developed a standardized analysis workflow for Illumina paired-end oomycete ITS metabarcodes that is applicable to future surveillance efforts. In total, 73 soil samples from the rhizosphere of woody plants from 33 genera, in addition to three samples from transport debris, were analysed by metabarcoding the ITS1 region with primers optimized for oomycetes. We detected various Phytophthora and Pythium species, with Pythium spp. being highly abundant in all samples. We also found that the baiting procedure, which included submerging the soil samples in water, resulted in the enrichment of organisms other than oomycetes, compared to non-baited soil samples.

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We studied the effect of three Pandora neoaphidis isolates from one Sitobion avenae population, three temperatures, and two aphid species namely S. avenae and Rhopalosiphum padi on (i) aphid mortality, (ii) time needed to kill aphids, and (iii) aphid average daily and lifetime fecundity. A total of 38% of S. avenae and 7% of R. padi died and supported fungus sporulation. S. avenae was killed 30% faster than R. padi. Average daily fecundity was negatively affected only in S. avenae inoculated with, but not killed by, P. neoaphidis. Nevertheless, lifetime fecundity of both aphid species inoculated and sporulating with P. neoaphidis was halved compared to lifetime fecundity of surviving aphids in the control. Increased temperature resulted in higher mortality rates but did not consistently affect lethal time or fecundity. Results suggest that (i) temperature effects on virulence differ between isolates, even when obtained within the same host population, and (ii) even though an isolate does not kill a host it may reduce its fecundity. Our findings are important for the understanding of P. neoaphidis epizootiology and for use in pest-natural enemy modelling.

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We determined how conidia of arthropod-pathogenic fungi on leaves affected the behavior of two predators—Orius majusculus (Hemiptera: Anthocoridae) and Phytoseiulus persimilis (Acari: Phytoseiidae)—when offered a choice between preying on two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), in the presence or absence of infective conidia of Metarhizium brunneum (Ascomycota: Hypocreales) and Neozygites floridana (Entomophthoromycota: Neozygitaceae). The results indicate no significant relation between the presence of conidia and predator behavior. The only indication of interference is between the generalists O. majusculus and M. brunneum, with a trend towards more time spent feeding and more prey encounters turning into feeding events on leaf discs without conidia than on leaf discs with conidia. Our results show that the presence of fungal conidia does not alter the preying behavior of the predators, and using predators and fungi together is not limited by any interference between organisms in the short term.

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Pandora neoaphidis and Entomophthora planchoniana are widespread and important specialist fungal pathogens of aphids in cereals (Sitobion avenae and Rhopalosiphum padi). The two aphid species share these pathogens and we compare factors influencing susceptibility and resistance. Among factors that may influence susceptibility and resistance are aphid behavior, conspecific versus heterospecific host, aphid morph, life cycle, and presence of protective endosymbionts. It seems that the conspecific host is more susceptible (less resistant) than the heterospecific host, and alates are more susceptible than apterae. We conceptualize the findings in a diagram showing possible transmission in field situations and we pinpoint where there are knowledge gaps.

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BACKGROUND Root inoculations of crop plants with beneficial fungi constitute a promising strategy for growth promotion and control of above‐ground pests and diseases. Here, strawberry roots (cultivar ‘Albion’ and ‘Pircinque’) were inoculated with 25 different Brazilian entomopathogenic fungal isolates of three genera and the effects on Tetranychus urticae oviposition and plant growth were evaluated in greenhouse experiments. RESULTS Reductions in the number of T. urticae eggs compared to control treatments were observed on both cultivars inoculated with almost all isolates. For the cultivar ‘Albion’, Metarhizium anisopliae (ESALQ 1604, ESALQ 1669), M. robertsii (ESALQ 1622, ESALQ 1635), Metarhizium sp. Indet. (ESALQ 1684) and Beauveria bassiana (ESALQ 3323) increased dry weight of roots and leaves, and fruit yield, while M. robertsii (ESALQ 1634), Metarhizium sp. Indet. (ESALQ 1637) and (ESALQ 1636) enhanced fruit yield and dry weight of leaves, respectively. For the cultivar ‘Pircinque’, M. anisopliae (ESALQ 1669) was the only isolate observed to increase dry weight of roots. CONCLUSION The results suggest that inoculation of strawberry roots with entomopathogenic fungi may be an innovative strategy for pest management above ground. Furthermore, these inoculations may also stimulate plant growth and strawberry production, but the effects depend on fungal strains and crop cultivar.

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God plantehelse er vesentlig for at vi skal få nok mat. Uten plantevern ville sju av ti planter blitt spist av skadedyr, ødelagt av sykdommer eller utkonkurrert av ugras. Kjemiske plantevernmidler kan imidlertid være skadelige for helse og miljø. Derfor trenger vi nye metoder som kan erstatte sprøytemidlene.

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The effect of inoculation of strawberry roots by two entomopathogenic fungal isolates, Metarhizium robertsii (ESALQ 1622) and Beauveria bassiana (ESALQ 3375), on naturally occurring arthropod pests and plant diseases was investigated in four commercial strawberry fields during two growing seasons in Brazil. Three locations represented open-field production while strawberries were grown in low tunnels at the fourth location. Population responses of predatory mites to the fungal treatments were also assessed. Plants inoculated by the fungal isolates resulted in significantly fewer Tetranychus urticae adults compared to control plants at all four locations. The mean cumulative numbers ± SE of T. urticae per leaflet were: M. robertsii (225.6 ± 59.32), B. bassiana (206.5 ± 51.48) and control (534.1 ± 115.55) at the three open-field locations, while at the location with tunnels numbers were: M. robertsii (79.7 ± 10.02), B. bassiana (107.7 ± 26.85) and control (207.4 ± 49.90). Plants treated with B. bassiana had 50% fewer leaves damaged by Coleoptera, while there were no effects on numbers of whiteflies and thrips. Further, lower proportions of leaflets with symptoms of the foliar plant pathogenic fungi Mycosphaerella fragariae and Pestalotia longisetula were observed in the M. robertsii (4.6% and 1.3%)- and B. bassiana (6.1% and 1.3%)-treated plots compared to control plots (9.8% and 3.7%). No effect was seen on numbers of naturally occurring predatory mites. Our results suggest that both isolates tested may be used as root inoculants of strawberries to protect against foliar pests, particularly spider mites, and also against foliar plant pathogenic fungi without harming naturally occurring and beneficial predatory mites.

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We investigated the ability of the fungal entomopathogen Beauveria bassiana strain GHA to endophytically colonize sugarcane (Saccharum officinarum) and its impact on plant growth. We used foliar spray, stem injection, and soil drench inoculation methods. All three inoculation methods resulted in B. bassiana colonizing sugarcane tissues. Extent of fungal colonization differed significantly with inoculation method (χ2 = 20.112, d. f. = 2, p < 0.001), and stem injection showed the highest colonization level followed by foliar spray and root drench. Extent of fungal colonization differed significantly with plant part (χ2 = 33.072, d. f. = 5, p < 0.001); stem injection resulted in B. bassiana colonization of the stem and to some extent leaves; foliar spray resulted in colonization of leaves and to some extent, the stem; and soil drench resulted in colonization of roots and to some extent the stem. Irrespective of inoculation method, B. bassiana colonization was 2.8 times lower at 14–16 d post inoculation (DPI) than at 7–10 DPI (p = 0.020). Spraying leaves and drenching the soil with B. bassiana significantly (p = 0.01) enhanced numbers of sett roots. This study demonstrates for the first time that B. bassiana can endophytically colonize sugarcane plants and enhance the root sett and it provides a starting point for exploring the use of this fungus as an endophyte in management of sugarcane pests.

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Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants—Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.

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Neozygites floridana is a pathogenic fungus and natural enemy of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), which is an important polyphagous plant pest. The aim of this study was to reveal and predict what combination of temperature, relative humidity (RH), and time that enables and promotes primary conidia production and capilliconidia formation in N. floridana (Brazilian isolate ESALQ 1420), in both a detached leaf assay mimicking climatic conditions in the leaf boundary layer and in a semi-field experiment. In the detached leaf assay, a significant number of conidia were produced at 90% RH but the highest total number of primary conidia and proportion of capilliconidia was found at 95 and 100% RH at 25 °C. Positive temperature and RH effects were observed and conidia production was highest in the 8 to 12 h interval. The semi-field experiment showed that for a >90% probability of N. floridana sporulation, a minimum of 6 h with RH >90% and 10 h with temperatures >21 °C, or 6 h with temperatures >21 °C and 15 h with RH >90% was needed. Our study identified suitable conditions for primary- and capilliconidia production in this Brazilian N. floridana isolate. This information provides an important base for building models of a Decision Support System (DSS) where this natural enemy may be used as a tool in Integrated Pest Management (IPM) and a base for developing in vivo production systems of N. floridana.

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The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in crop residues, weeds, and soil sampled from a selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. The different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence of F. langsethiae in oat. Results show that F. langsethiae DNA may occur in the oat plant already before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. No Fusarium DNA was detected in soil samples. Of the arthropods that were associated with the collected oat plants, aphids and thrips species were dominating. Further details will be given at the meeting.

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The aim of this study was to evaluate the natural occurrence of Beauveria spp. in soil, from infections in the stink bug Piezodorus guildinii, an important pest of common bean (Phaseolus vulgaris) and as endophytes in bean plant tissue. Twelve conventional and 12 organic common bean fields in the Villa Clara province, Cuba were sampled from September 2014 to April 2015. One hundred and fifty Beauveria isolates were obtained from soil samples, bean plant parts and stink bugs. The overall frequency of occurrence of Beauveria isolates in conventional fields (8.4%) was significantly lower than that in organic fields (23.6%). Beauveria were also obtained significantly more frequently from bean roots in organic fields (15.0%) compared to bean roots in conventional fields (3.3%). DNA sequencing of the intergenic Bloc region was performed for Beauveria species identification. All isolates where characterized as Beauveria bassiana (Balsamo-Crivelli) Vuillemin, and clustered with isolates of neotropical origin previously described as AFNEO_1. The Cuban B. bassiana isolates formed five clusters in the phylogeny. Isolates of two clusters originated from all four locations, organic and conventional fields, as well as soil, plants and stink bugs. Organic fields contained isolates of all five clusters while conventional fields only harbored isolates of the two most frequent ones. Mating type PCR assays revealed that mating type distribution was skewed, with MAT1/MAT2 proportion of 146/4, indicating limited potential for recombination. The present study is the first to report of B. bassiana as a naturally occurring endophyte in common bean. Further, it shows that B. bassiana occurs naturally in diverse environments of common bean fields, and constitutes a potential reservoir of natural enemies against pest insects particularly in organic fields.

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Despite global deforestation some regions, such as Europe, are currently experiencing rapid reforestation. Some of this is unintended woodland encroachment onto farmland as a result of reduced livestock pasture management. Our aim was to determine the likely impacts of this on exposure to ticks and tickborne disease risk for sheep in Norway, a country experiencing ecosystem changes through rapid woodland encroachment as well as increases in abundance and distribution of Ixodes ricinus ticks and tick-borne disease incidence. We conducted surveys of I. ricinus ticks on ground vegetation using cloth lure transects and counts of ticks biting lambs on spring pastures, where lambs are exposed to infection with Anaplasma phagocytophilum, the causative agent of tick-borne fever in livestock. Pastures had higher densities of I. ricinus ticks on the ground vegetation and more ticks biting lambs if there was more tree cover in or adjacent to pastures. Importantly, there was a close correlation between questing tick density on pastures and counts of ticks biting lambs on the same pasture, indicating that cloth lure transects are a good proxy of risk to livestock of tick exposure and tick-borne disease. These findings can inform policy on environmental tick control measures such as habitat management, choice of livestock grazing area and off-host application of tick control agents.

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Fields experiments were conducted during two growing seasons (2010–2011 and 2012–2013) at three seeding dates to identify stink bug (Hemiptera: Pentatomidae) species and to determine their seasonal population density fluctuation and damage caused to three common bean (Phaseolus vulgaris L.) cultivars “Ica Pijao,” “Cubacueto 25–9,” and “Chévere.” Stink bug species observed were Nezara viridula (L.), Piezodorus guildinii (Westwood), Chinavia rolstoni (Rolston), Chinavia marginatum (Palisot de Beauvois), and Euschistus sp. The most prevalent species was N. viridula in both seasons. The largest number of stink bugs was found in beans seeded at the first (mid September) and third (beginning of January) seeding dates. Population peaked at BBCH 75 with 1.75, 0.43, and 1.25 stink bugs/10 plants in 2010–2011 and with 2.67, 0.45, and 1.3 stink bugs/10 plants in 2012–2013 in the fields seeded the first, second, and third seeding dates, respectively. The lowest numbers of stink bugs were found in beans seeded at the second (mid November) seeding date. A significant negative correlation between relative humidity and number of stink bugs was found in 2010–2011, and a similar tendency was observed in 2012–2013. The highest seed and pod damage levels occurred in cv. “Chévere” and the lowest in cv. “ICA Pijao” during both seasons. Results suggest that cv. “ICA Pijao” and the second (mid November) seeding date is the best choice to reduce stink bug damage.

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Researchers in plant pathology and entomology often study the interaction between a host plant and its pathogen or an insect pest separately. Although studying single pathogen or insect interactions with a host plant is critical to understand the basic infection processes and to model each disease or pest attack separately, this is an extreme simplification of nature’s complexity, where multiple pests and pathogens often appear in parallel and interact with each other and their host plant. Effective management of pests and diseases require understanding of the complex interaction beteween diseases and pests on the host. Under natural conditions, wheat plants are subjected to attack by several insects and pathogens simultaneously or sequentially. The Bird cherry-oat aphid (Rhopalosiphum padi) and the necrotrophic pathogen Parastagonospora nodorum (syn. Stagonospora nodorum) the causal agent of Stagonospora nodorum blotch (SNB) are economically important pests of wheat in Norway. Since they colonize a common host, they may interact directly through competition for resources or indirectly by affecting the host response either positively (induced resistance) or negatively (induced susceptibility or biopredisposition). The effect of aphid infestation on P. nodorum infection and development of the disease could be an important factor in predicting SNB epidemics. However, studies on this multitrophic interactions are scarce. We conducted controlled greenhouse experiments to study the effect of aphid infestation on subsequent SNB development. The wheat cultivar ‘Bjarne’ was treated as follows:1) Aphid infested + insecticide sprayed + P. nodorum inoculated; 2) Insecticide sprayed + P. nodorum inoculated; 3) Water sprayed + P. nodorum inoculated; 4) Control plants (without aphid, insecticide or P. nodorum). When plants were at ca. BBCH 37, 18 adult female aphids (R. padi) were released per pot (treatment 1). Aphid inoculated plants were kept in an insect proof cage in a greenhouse compartment at 20°C, 70% RH, and 16 h photoperiod. Plants for the other treatments were kept in separate insect proof cages in the same greenhouse. Ten days after aphid release, plants infested with aphids (treatment 1) were sprayed with the insecticide BISCAYA (a.i. thiacloprid) at recommended concentration to remove aphids. Plants in treatment 2 and 3 were sprayed with the insecticide and water, respectively. Twenty-four hours after application of the insecticide or water, plants in treatment 1, 2, and 3 were inoculated with P. nodorum spore suspension (106 spores ml-1). The experiment included three replicates and was repeated two times. SNB incidence and severity were recorded. SNB incidence and severity were significantly higher on aphid infested plants than on non-infested plants (P < 0.05). Ten days after P. nodorum inoculation, disease severity were about 3-fold higher on aphid infested plants (treatment 1) than on non-infested plants (treatment 2 and 3). Plants in the blank control (treatment 4) were free of aphids and showed no symptoms of SNB . Infestation of wheat plants by the bird cherry-oat aphid prior to fungal inoculation enhanced the severity of SNB. P. nodorum is a necrotrophic pathogen that lives on nutrients from disintegrated plant cells. The increase in severity of SNB on aphid infested plants could be due to the increased number of dead or dying cells around the aphids feeding sites. However, whether aphids activity induced local or systemic susceptbility to plants is not yet known and needs to be studied further.

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In this chapter we will focus on the tick Ixodes ricinus, with its main geographical distribution in Europe. It is known to transmit a variety of pathogens, among them Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis. Tick population control is one of the measures to reduce the incidence of tick-borne diseases. Due to non-target effects of chemical acaricides, acquired resistance against chemical acaricides and increased regulations, there is a demand for sustainable control measures that may be used in integrated vector management (IVM) of ticks. This chapter describes and evaluates the present knowledge on biological control of I. ricinus as an alternative to the use of chemical acaricides. Biological control makes use of living organisms (e.g. fungi, bacteria, nematodes, invertebrate predators, parasitoids) to suppress a pest population. The natural occurrence of these organisms in I. ricinus and the use of these organisms as biological control agents against I. ricinus are reviewed. Entomopathogenic fungi (Beauveria and Metarhizium spp.) are the most commonly used biocontrol agents against ticks. A variety of nematode species are also shown to be effective against different tick species, but the knowledge on the operational use of invertebrate predators and parasitoids to control ticks is limited. We conclude that there are several candidates for the biological control of ticks, but that the knowledge on the natural occurrence and efficacy of these to control I. ricinus populations is very limited. There is, therefore, a need of more studies on naturally occurring enemies of I. ricinus to be able to suggest possible biocontrol candidates. These candidates should be tested in controlled laboratory and field studies with the aim to develop elegant, precise and effective biocontrol strategies for the control of I. ricinus that may be used alone or in combination with other control strategies in IVM.

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Aphids in cereals are an important problem in Europe. Entomopathogenic fungi in the Phylum Entomophthoromycota are among their natural enemies. Under certain conditions, they can cause epizootic events and control pest aphid populations. This epizootic development is affected by many abiotic and biotic factors such as aphid species and their host plant (including weeds within the crop), fungal species and isolates, and temperature. Studies from Denmark, UK, Slovakia and suggest that the genus Pandora is the most prevalent fungal pathogen of the English grain aphid (Sitobion avenae). Which fungal species that is the most prevalent in populations of the other important aphid species in cereals in Europe, the Bird cherry-oat aphid (Rhopalosiphum padi), is less clear. We chose, however, to use Pandora to assess the biological control potential of Entomophthoromycota against aphids in cereals and to produce data that might be used in a pest-warning model incorporating the effect of this natural enemy. This was done by conducting laboratory studies on the virulence of two Pandora isolates (collected in the same field) on R. padi and Myzus persicae at three temperatures (12, 15 and 18◦C). M. persicae is a polyphagous aphid that may be present on weeds. It can be an alternative host for Pandora and hence might also affect the epidemic development of Pandora in aphids that are cereal pests. Our preliminary results show that R. padi is more resistant to the tested Pandora isolates than M. persicae. The two Pandora isolates had different virulence in the two aphid species tested. The temperature did not influence the virulence.

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This contribution demonstrates an example of experimental automatic image analysis to detect spores prepared on microscope slides derived from trapping. The application is to monitor aerial spore counts of the entomopathogenic fungus Pandora neoaphidis which may serve as a biological control agent for aphids. Automatic detection of such spores can therefore play a role in plant protection. The present approach for such detection is a modification of traditional manual microscopy of prepared slides, where autonomous image recording precedes computerised image analysis. The purpose of the present image analysis is to support human visual inspection of imagery data – not to replace it. The workflow has three components: • Preparation of slides for microscopy. • Image recording. • Computerised image processing where the initial part is, as usual, segmentation depending on the actual data product. Then comes identification of blobs, calculation of principal axes of blobs, symmetry operations and projection on a three parameter egg shape space.

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Tick-borne diseases, such as anaplasmosis and babesiosis, are of major concern for Norwegian sheep farmers. Ticks can be controlled on and off the host, usually with the long-term, high-rotation use of chemicals. Fungal pathogens, predatory mites and ants are thought to be important tick killers in nature. However, the prevalence and diversity of predatory mites in tick habitats has barely been evaluated. It is known that most soil mite species of the cohort Gamasina (order Mesostigmata) are predators. Until now, 220 mesostigmatid species have been reported from Norway, most of them belonging to the Gamasina. One of the first recommended steps in a biological control program involves the determination of the fauna in the pest habitat. The objective of this study was to determine the groups of gamasines co-occurring with I. ricinus in sheep grazing areas in Isfjorden and Tingvoll in Western Norway. A total of 2,900 gamasines of 12 families was collected. The most numerous families were Parasitidae (46.9%) and Veigaiidae (25.7%), whereas the most diverse families were Laelapidae, Macrochelidae, Parasitidae and Zerconidae. Our results showed that the tick density was significantly related only to locality, elevation and rainfall. Differences in the prevailing environmental conditions resulted in more outstanding differences between Gamasina abundances than diversities. Based on our present knowledge of the potential of different gamasine groups as biological control agents, the results suggested that laelapid mites should be among the priority groups to be further evaluated for their role in the natural control of I. ricinus in Norway.

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The two-spotted spider mite, Tetranychus urticae, is a serious pest of numerous crops worldwide. Sustainable management solutions for T. urticae include predators and entomopathogens. Neozygites floridana is a naturally occurring obligate fungal pathogen of T. urticae and can cause declines in T. urticae populations. The purpose of this study was to determine whether releasing the predatory mite Phytoseiulus persimilis into T. urticae populations has the potential to increase transmission of N. floridana and accelerate the development of an epizootic. This is the first study quantifying the effect of P. persimilis on transmission of N. floridana to T. urticae in a controlled microcosm study. Our results show that introducing P. persimilis into T. urticae, populations increased the proportion of T. urticae infected with N. floridana. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted. We suggest that releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone.

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A controlled climatic chamber microcosm experiment was conducted to examine how light affects the hourly sporulation pattern of the beneficial mite pathogenic fungus Neozygites floridana during a 24 h cyclus over a period of eight consecutive days. This was done by inoculating two-spotted spider mites (Tetranychus urticae) with N. floridana and placing them on strawberry plants for death and sporulation. Spore (primary conidia) discharge was observed by using a spore trap. Two light regimes were tested: Plant growth light of 150 μmol m−2 s−1 for 12 h supplied by high pressure sodium lamps (HPS), followed by either; (i) 4 h of 50 μmol m−2 s−1 light with similar HPS lamps followed by 8 h darkness (full HPS light + reduced HPS light + darkness) or (ii) 4 h of 50 μmol m−2 s−1 red light followed by 8 h darkness (full HPS light + red light + darkness). A clear difference in hourly primary conidia discharge pattern between the two different light treatments was seen and a significant interaction effect between light treatment and hour in day during the 24 h cycle was observed. The primary conidia discharge peak for treatment (ii) that included red light was mainly reached within the red light hours (19:00–23:00) and the dark hours (23:00–07:00). The primary conidia discharge peak for treatment (i) with HPS light only was mainly reached within the dark hours (23:00–07:00).

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Introducing the predatory mite Phytoseiulus persimilis into two-spotted spider mite, Tetranychus urticae, populations significantly increased the proportion of T. urticae infected with the spider mite pathogen Neozygites floridana in one of two experiments. By the final sampling occasion, the number of T. urticae in the treatment with both the predator and the pathogen had declined to zero in both experiments, while in the fungus-only treatment T. urticae populations still persisted (20–40 T. urticae/subsample). Releasing P. persimilis into crops in which N. floridana is naturally present has the potential to improve spider mite control more than through predation alone.

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The aim of this study was to evaluate the effect of conventional versus organic common bean (Phaseolus vulgaris) production on natural occurrence of Beauveria spp. as entophytes in bean plant tissue, from soil and as infections in stink bugs (Hemiptera: Pentatomidae), an important pest of bean in Cuba. Twenty-four organic and conventionally managed bean fields were sampled from September 2014 to April 2015 and Beauveria spp. were isolated and DNA extracted. PCR amplification of the intergenic Bloc region was performed for the identification of Beauveria species. Eighty-seven isolates were obtained from the soil samples by using the Galleria mellonella baiting technique. Further, 45 isolates were obtained from endophytic tissues of bean plant parts and 18 isolates were acquired from stink bugs. Only Beauveria bassiana was identified by DNA sequencing in this material. B. bassiana was more prevalent in soil, plant and stink bugs sampled from organic fields (41% soil, 22% plant, 9% bugs) compared to conventional fields (17% soil, 8% plant, 2% bugs). All plant parts were colonized by B. bassiana, but a significantly higher occurrence of this fungus was found in roots (9%) compared to stems (6%), leaves (4%) and pods (2%) in organic fields. In conventional fields there was a significantly higher occurrence of B. bassiana acquired from root (4%) and stem (3%) compared to leaves (1%) and pods (1%). Mating type PCR assays revealed that each of the isolates carried single mating types, with frequencies of 146/150 (MAT1) and 4/150 (MAT2), indicating limited potential for recombination. Our findings show that B. bassiana occur naturally as endophytes in bean fields in Cuba and contribute to a better ecological understanding of B. bassiana in agriculture.

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Background. The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. Results. Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. Conclusion. The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry

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The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in weeds, crop residues, and soil, sampled from a predetermined selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. All the different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence F. langsethiae in oat. Preliminary results show that F. langsethiae DNA may occur in the oat plant before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. More results from this work will be presented at the meeting.

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The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in weeds, crop residues, and soil, sampled from a predetermined selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. All the different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence F. langsethiae in oat. Preliminary results show that F. langsethiae DNA may occur in the oat plant before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. More results from this work will be presented at the meeting.

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Bladlusoverført virus er et problem i potet i Norge. Hvert år er det settepotetpartier i den sertifiserte avlen som ikke kan godkjennes fordi innholdet av PVY/PVA er for høye. For høyt virusinnhold i potetprodusentenes egen oppformering er også et problem. For årene 2008, 2009, 2010 og 2011 har det blitt sendt inn virusprøver til NAK (Nederland) fra egne oppformerte settepoteter hos potetdyrkerne. Resultatene viste høye innhold av både PVA og PVY. Dette kan fort gi store avlingstap. I Norge har vi ikke god nok kunnskap om hvilke lusarter som herjer i potetåkre. Med bakgrunn i problemstillingen skissert over ønsket Norsk Landbruksrådgiving at Bioforsk Plantehelse skulle opparbeider seg mer kunnskap om følgende: Hvilke bladlusarter er det i norske potetåkre? Prosjekt: Kartlegging av bladlusarter i potetåkre. Hvor aktive er de i overføring av virus? Hvilken skade gjør disse bladlusartene i potetåkre i Norge? Prosjekt: Forsøk i potetåker med bladlusproblemer. Hvordan kan lus i potet overvåkes, for dermed å sette inn riktig tiltak til rett tid, slik at skader ikke oppstår i avlinga. For eksempel få til en ”indeks” (terskel) som ut fra bladluspopulasjonen angir når riset skal fjernes for å redusere virusmengden i settepotetene. Prosjekt: Vurderes når kartlegging og resultater fra forsøk er ”på plass”

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The use of Chinese cabbage as a trap crop where insect pathogenic fungi may prolifereate has been tested in a series of push-pull strategy experiments both in the laboratory and in the field. The pest species studied are the cabbage- and turnip root fly (Delia radicum and D. floralis). In a dual choice laboratory experiment, both healthy and Entomophthora muscae inoculated D. floralis were tested for choice of plant for oviposition. The choices were 1) Broccoli against Broccoli 2) Chinese cabbage against Broccoli 3) Broccoli against Broccoli under sown with clover 4) Chinese cabbage against Broccoli under sown with clover. In a semi-field pilot study with Broccoli and Chinese cabbage the choice between main - and trap crop for healthy and inoculated flies, as well as fungal transmission between flies over time, was studied. A pilot field study has also been performed to investigate the overall effect of using Chinese cabbage as a trap crop as well as studying the spatial distribution of Delia eggs in a cabbage field. The results from the dual choice experiment and both pilot studies indicates that using Chinese cabbage as a trap crop is a promising strategy for the management of D. radicum and D. floralis, both as a oviposition attractant and as a trap crop where insect pathogenic fungi may proliferate and kill the adult flies.  

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Strawberry production in high plastic tunnels is becoming popular for the advantages of extended production and reduced disease problems. However, this production system creates favorable conditions for several pests, including the two-spotted spider mite (Tetranychus urticae) and for some diseases, of which powdery mildew (Podosphaera aphanis) is the most important. Preliminary laboratory experiments were conducted to study: (1) the preference of T. urticae to mildew infected vs. healthy strawberry leaves, and (2) the impact of powdery mildew on T. urticae egg production and predation of the predatory mite Phytoseiulus persimilis. Five days after the mite release, the total number of T. urticae eggs and nymphs found on healthy leaf discs were two times higher than on leaf discs with powdery mildew, predatory mites or both. In the preference experiment, a significant number of T. urticae moved to healthy strawberry leaf discs and settled there for the whole period of the experiment. The results indicated that T. urticae did not thrive on strawberry leaves heavily infested with powdery mildew, and that powdery mildew seemed to reduce the predation efficiency of P. persimilis. Therefore, it may be economical and efficient to control powdery mildew before releasing P. persimilis to control the spider mites.  

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  The mite-pathogenic fungus Neozygites floridana and N. tanajoae are important natural enemies of spider mites and are good candidates for microbial control. To be able to succeed in using Neozygites for the microbial control of spider mites we need to understand the factors that affect a Neozygites epidemic development. Studies have therefore been conducted with Brazilian and Norwegian isolates of these fungi to reveal the effect of abiotic (temperature, rainfall, humidity, light, pesticides) and biotic factors (host plant, presence of predators) on the fungal performance and epizootic development in cassava green mite, tomato red spider mite and twospotted spider mite populations. For Brazilian isolates, rainfalls do not seem to have an apparent impact on disease progression. Microclimatic humidity seems, however, to be a critical factor. When placed on microscope slides, these two fungi only sporulate at RH≥95%, while   N. floridana-killed cadavers of the twospotted spider mite placed within the boundary layer of the abaxial side of a leaf sporulated also at 90% RH. The temperature optimum of Brazilian and Norwegian isolates varies and Brazilian isolates can sporulate at temperatures as low as 13°C but the highest production of capilliconidia occurs at 21-25°C. A Norwegian N. floridana isolate tested produces the highest numbers of primary conidia at 13°C and 18°C while 23°C resulted in a lower production. Our studies also show that performance of different N. floridana isolates may vary with light duration and intensity. In integrated pest management systems, Neozygites needs to be compatible with chemical pesticides. Our studies show, however, that several fungicides affect N. floridana negatively. Our studies have also shown that performance of Neozygites vary with host plants.    

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

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The two spotted spider mite Tetranychus urticae is known to overwinter as hibernating females, and these partly inactive females may harbour Neozygites floridana. N. floridana is a fungal natural enemy of spider mites. The aim of this study was therefore to investigate whether N. floridana may be present inside living hibernating females of T. urticae throughout the winter season, and if so, in what prevalence and what stage of its fungal life cycle. Hibernating T. urticae females were investigated for the presence of fungal structures throughout one winter (October 12, 2006 to February 19, 2007) in field-grown strawberries in a cold climate in Norway (min. ambient temp -15.3oC). The study confirmed that N. floridana survived the winter as a semilatent hyphal body infection, protected inside live hibernating females. The beneficial fungus N. floridana is therefore ready to develop and sporulate as soon as climatic conditions permits, resulting in early season infection of T. urticae. An early-season infection of N. floridana that may result in the control of T. urticae in strawberries is important, since T. urticae is known to cause reductions in strawberry yield at much lower population levels in early season than in late season. For N. floridana to control T. urticae populations early in the spring, factors important for sporulation and dissemination of the fungus needs to be favoured. The adapted use of pesticides, especially fungicides might therefore be very important at this time of the year.  

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In this review, we provide an overview of the role of glucosinolates and other phytochemical compounds present in the Brassicaceae in relation to plant protection and human health. Current knowledge of the factors that influence phytochemical content and profile in the Brassicaceae is also summarized and multi-factorial approaches are briefly discussed. Variation in agronomic conditions (plant species, cultivar, developmental stage, plant organ, plant competition, fertilization, pH), season, climatic factors, water availability, light (intensity, quality, duration) and CO2 are known to significantly affect content and profile of phytochemicals. Phytochemicals such as the glucosinolates and leaf surface waxes play an important role in interactions with pests and pathogens. Factors that affect production of phytochemicals are important when designing plant protection strategies that exploit these compounds to minimize crop damage caused by plant pests and pathogens. Brassicaceous plants are consumed increasingly for possible health benefits, for example, glucosinolate-derived effects on degenerative diseases such as cancer, cardiovascular and neurodegenerative diseases. Thus, factors influencing phytochemical content and profile in the production of brassicaceous plants are worth considering both for plant and human health. Even though it is known that factors that influence phytochemical content and profile may interact, studies of plant compounds were, until recently, restricted by methods allowing only a reductionistic approach. It is now possible to design multi-factorial experiments that simulate their combined effects. This will provide important information to ecologists, plant breeders and agronomists.

Sammendrag

Potensiell avlingsreduksjon pga ugras, skadedyr og plantesykdommer ligger på hhv 34%, 18% og 16%. En så stor potensiell tapspost krever godt plantevern. Hvilke skadegjørere vi vil få et økt problem med og hvilke som vil bli redusert pga endret klima, er det viktig å få en oversikt over slik at tilpassede planteverntiltak kan utvikles. Klimatilpasningskompetansen til rådgiving og bønder må bygges opp gradvis. Forskningen må starte nå.

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In a series of tritrophic-level interaction experiments, the effect of selected host plants of the spider mites, Tetranychus evansi and Tetranychus urticae, on Neozygites floridana was studied by evaluating the attachment of capilliconidia, presence of hyphal bodies in the infected mites, mortality from fungal infection, mummification and sporulation from fungus-killed mite cadavers. Host plants tested for T. evansi were tomato, cherry tomato, eggplant, nightshade, and pepper while host plants tested for T. urticae were strawberry, jack bean, cotton and Gerbera. Oviposition rate of the mites on each plant was determined to infer host plant suitability while host-switching determined antibiosis effect on fungal activity. T. evansi had a high oviposition on eggplant, tomato and nightshade but not on cherry tomato and pepper. T. urticae on jack bean resulted in a higher oviposition than on strawberry, cotton and Gerbera. Attachment of capilliconidia to the T. evansi body, presence of hyphal bodies in infected T. evansi and mortality from fungal infection were significantly higher on pepper, nightshade and tomato. The highest level of T. evansi mummification was observed on tomato. T. evansi cadavers from tomato and eggplant produced more primary conidia than those from cherry tomato, nightshade and pepper. Switching N. floridana infected T. evansi from one of five Solanaceous host plants to tomato had no prominent effect on N. floridana performance. For T. urticae, strawberry and jack bean provided the best N. floridana performance when considering all measured parameters. Strawberry also had the highest primary conidia production. This study shows that performance of N. floridana can vary with host plants and may be an important factor for the development of N. floridana epizootics.

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

A successful push-pull strategy needs to include means to kill pest insects in order to control and reduce the pest population. The use of Chinese cabbage as a trap crop where insect pathogenic fungi may proliferate has been tested in a series of push-pull strategy experiments both in the laboratory, in semi-field and field. In this work, the aim is to develop a push-pull-kill strategy in which the transmission of the entomopathogenic fungi Entomophthora muscae is facilitated with the aim to reduce the population of cabbage- and turnip root flies (Delia radicum and Delia floralis). In the lab experiment, Chinese cabbage proved to be more attractive compared to Broccoli and Broccoli undersown with red clover, for oviposition of both healthy and E. muscae infected D. floralis females. Infected flies also died and sporulated on or near the Chinese cabbage. This pattern was also evident in a preliminary field study in which sporulating Delia spp. cadavers were found on Chinese cabbage only. These results indicate that Chinese cabbage may be used as a trap crop for D. floralis oviposition, but it may also be a sink where healthy flies become infected through contact with sporulating cadavers. This summer, we tested the strategy in larger scale and under more natural conditions in a semi-field study. Healthy D. floralis were released in cages with Broccoli and Chinese cabbage plants, with or without the presence of E. muscae infected D. radicum. Our hypothesis were that 1) D. floralis released in cages with infected flies will be infected, and die and sporulate on or near the Chinese cabbage, 2) Fewer eggs will be laid by D. floralis in cages with infection compared to control cages, 3) More D. floralis eggs will be laid on Chinese cabbage compared to Broccoli. The results from the semi field study strenghtens our previous results which showed that using Chinese cabbage as a trap crop is a promising strategy for the management of D. floralis and D. radicum, both as an oviposition attractant and as a source for fungal transmission between flies.

Sammendrag

Forsøksresultatene som presenteres i denne rapporten er biologisk godkjenningsprøving av skadedyrmidler på oppdrag fra Mattilsynet i 2010. I tillegg er det forsøk eller egne forsøksledd som grupperes som biologisk utviklingsprøving. Utviklingsprøvingen er finansiert av Bioforsk, importører/tilvirkere av plantevernmidler, produsentgrupper eller av Landbruks- og matdepartementet. Forsøkene er utført etter GEP-kvalitet, hvis ikke annet er nevnt. Enheter i Norsk Landbruksrådgiving (tidl. forsøksringene) gjør en stor egeninnsats i disse forsøkene. For eventuelle restanalyseforsøk, er kjemiske analyser utført av Fagseksjon Pesticidkjemi ved Bioforsk Plantehelse.

Sammendrag

The co-occurrence of powdery mildew, Podosphaera aphanis, and the two-spotted spider mite, Tetranychus urticae, on strawberry plants requires a strategic use of fungicides to control powdery mildew without harming predatory mites and other beneficial organisms. Sulfur has been used for two centuries to manage powdery mildew and is the only fungicide approved for use in organic strawberry production in Norway. However, there are contrasting reports in the literature about the effect of sulfur on predatory mites and two-spotted spider mite from field studies. Controlled laboratory experiments were therefore conducted on strawberry leaf disks to study the main as well as the interacting effects of sulfur on P. aphanis, T. urticae and the predatory mite, Phytoseiulus persimilis. The following seven treatment combinations: 1) Sulfur + P. aphanis 2) Sulfur + T. urticae 3) Sulfur + P. persimilis 4) Sulfur + P.aphanis + P.persimilis 5) Sulfur + P.aphanis + T.urticae 6) Sulfur + P. Persimilis + T.urticae 7) Sulfur + P.aphanis + P.persimilis + T.urticae and seven parallel treatment combinations with water instead of sulfur (control) were used. Leaf disks were dipped in a sulfur (Thiovit Jet) solution or water and inoculated with P. aphanis after the sulfur/ water had dried on the leaf surface. In treatments with mites, five female T. urticae and one female P. persimilis were added per leaf disk.  Preliminary analysis of the results showed that only the predatory mite and sulfur significantly (P ≤ 0.05) affected egg production and mortality of T. urticae. In the treatment that combined sulfur + P. aphanis + P. persimilis + T. urticae a significantly reduction in T. urticae egg production was seen.   However, there was no significant effect on egg production and mortality of T. urticae in the three-way or two-way interactions of sulfur, powdery mildew and predatory mite. There was no significant effect of sulfur on mortality of P. persimilis, and sulfur did not seem to affect the efficiency of this predatory mite. Powdery mildew did not affect T. urticae probably because the mildew was not well developed due to inoculation at the same time as the mites were added. In another experiment, however, mites were released on leaf disks that had well developed powdery mildew, and here a negative effect of the mildew on T. urticae egg production was clearly seen.

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

In this study we aimed at understanding the mechanisms that affects an epidemic development of Neozygites floridana in a Tetranychus urticae population. This was done by comparing how many spores a cadaver infected with a N. floridana isolate could produce and at what distance and in which directions they could be thrown on a coverslip at temperatures relevant to the northern hemisphere (13, 18 and 23oC). The highest number of spores were produced at 13oC at a number of 1886. Numbers of spores thrown at 18oC and 23oC were 1733 and 1302 respectively. Temperature had a significant effect on sporulation. Most of the spores were thrown at a distance of 0-0.6 mm from the cadaver. Cadavers placed on the underside of a coverslip were able to throw spores back up on the coverslip surface. A whole plant bioassay was also conducted to reveal where on a plant T. urticae infected with N. floridana die and sporulate. Cadavers showed a different verical distribution on the cucumber plant compared to healthy spider mites. Most of the cadavers were located at the lower to the middle part of the plant, while healthy spider mites were more evenly distributed on the whole plant.

Sammendrag

Resistens eller nedsatt følsomhet mot kjemiske skadedyrmidler er funnet hos flere skadedyrarter i bl.a. oljevekster, jordbær, potet og prydplanter i veksthus. Dette fører til bekjempelsesproblemer, økt sprøyting og risiko for resistens mot nye midler.

Sammendrag

The vine weevil, Othiorynchus sulcatus, is a serious pest in strawberries and biological control methods are needed to combat this pest. Formulations of the insect pathogenic fungus Metarhizium anisopliae is registered for use against Otiorhynchus spp. in several countries but no fungal control agents are avilable for control of O. sulcatus in Norway. All developmental stages of Otiorhynchus spp. are susceptible to virulent insect pathogenic fungal species, but best control has been achieved against the larvae (Moorhouse et al. 1992). A number of studies have shown that M. anisopliae and Beauveria bassiana have good potential against Otiorhynchus spp. (Cross et al. 2001). In field grown strawberries, good control with Metarhizium has been reported when environmental conditions for the fungus are favourable (Oakley 1994). Temperatures in excess of 15oC are required for good control by most fungal isolates. Low temperature is therefore a major restricting factor for use of fungi outdoors (Gillespie et al. 1989, Soares et al. 1983). Isolates with low temperature optimums could therefore be well suited for field conditions in Northern Europe, where soil temperatures at the time when most larvae are found in the soil in autumn are 10-12oC. Norwegian M. anisopliae and B. bassiana isolates have shown promising results against O. sulcatus larvae at low temperatures in laboratory bioassays (Hjeljord & Klingen 2005). One of the Norwegian M. anisopliae isolates has also shown good competition with other soil fungi in laboratory experiments (Hjeljord & Meadow 2005). In addition to being cold tolerant, rhizosphere competence is important for fungal control agents that are used to control root feeding pests. "Rhizosphere competence" has been defined when considering biological control agents as "the ability of a microorganism, applied by seed treatment, to colonize the rhizosphere of developing roots" (Baker 1991). In this study we therefore aimed at testing the survival and rhizosphere competence of two different cold active Norwegian isolates (M. anisopliae isolate NCRI 250/02 and B. bassiana NCRI 12/96) in a semi field experiment in Norway. These were compared with the commercially avilable M. anisopliae isolate Ma43 originating from Austria (the isolate is also known to have many other names (Eilenberg 2008)). The study was conducted by estimating fungal concentrations in the bulk and rhizosphere soil surrounding the strawberry plant roots by counting colony forming unists (CFUs). The highest numbers of B. bassiana NCRI 12/96 CFUs were seen in the rhizosphere at 1.87x109 per liter soil 3 months after application. The highest numbers of M. anisopliae NCRI 250/02 CFUs were seen in the rhizosphere at 2.41x109 per liter soil 1 year after application. Numbers of CFUs for the M. ansiopliae Ma43 CFUs were generally lower than for the Norwegian isolates, but also for this isolate a higher fungal concentration was found in the rihzosphere soil than in the bulk soil.

Sammendrag

The vine weevil, Othiorynchus sulcatus, is a serious pest in strawberries in Norway and biological control methods are needed to combat this pest. In this study, the rhizosphere competence of two cold active Norwegian fungal isolates (Metarhizium anisopliae isolate NCRI 250/02 and Beauveria bassiana NCRI 12/96) and the well known Ma43 originating from Austria were tested. This was done by estimating fungal concentrations in the bulk and rhizosphere soil surrounding the strawberry plant roots by counting colony forming unists (CFUs). The highest numbers of B. bassiana NCRI 12/96 CFUs were seen in the rhizosphere at 1.87x109 per liter soil 3 months after application. The highest numbers of M. anisopliae NCRI 250/02 CFUs were seen in the rhizosphere at 2.41x109 per liter soil 1 year after application. Numbers of CFUs for the M. ansiopliae Ma43 CFUs were generally lower than for the Norwegian isolates, but also for this isolate a higher fungal concentration was found in the rihzosphere soil than in the bulk soil.

Sammendrag

Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest in the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies: 1) When, and at what infection levels does N. floridana occur in T. urticae populations in field grown strawberries in Norway? 2) How does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) Where do N. floridana infected T. urticae move and sporulate on a plant? 4) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that the N. floridana infection level varies considerably throughout a season. T. urticae killed by N. floridana was found to sporulate surprisingly early in the season (first observation March 18) and infection early in the season is important for a good control of T. urticae. N. floridana was observed to over-winter as hyphal bodies in hibernating T. urticae females throughout the winter. Cadavers with resting spores were found from October to the end of January only. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures relevant to Norwegian conditions (13o, 18o, 23o C), results show that the highest numbers of spores (1886 and 1733 per cadaver) were thrown at 13o and 18o compared to 23o C (1302 per cadaver). Spores were thrown at the same distance (up to about 6 mm) at all three temperatures. These results show that the fungus may be a promising agent at temperatures relevant for strawberry production in countries located in Northern areas. Our attempt to inoculate N. floridana artificially in a strawberry field and also in greenhouse cucumbers has not been successful yet, but we are working to improve the methods in a new project titled "BERRYSYS -A system approach to biocontrol in organic and integrated strawberry production".

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

Neozygites floridana is a fungus in the order Entomophthorales that is a natural enemy of several spider mite species including the two-spotted spider mite, Tetranychus urticae. When conditions are right, this fungus may cause epizootics in spider mite populations and kill high numbers of mites. The fungus is therefore promising for biological control of T. urticae in strawberry and can be used in combination with other pest management strategies. Our previous studies have shown that N. floridana is compatible with other biocontrol methods such as predatory mites. Phytoseiulus longipes fed on fungus-infected T. urticae laid equal number of eggs to those fed on healthy prey. This indicates that the fungus does not affect this predatory mite negatively. In a choice experiment (hosts with and without N. floridana), P. longipes fed indiscriminately irrespective of the presence of the fungus. The compatibility of biological control methods with pesticides is of great importance for an integrated pest management system to work well. Some acaricides and fungicides have the potential to affect both beneficial fungi and predatory mites and careful selection of pesticides that are not harmful to these beneficial organisms can promote their biocontrol potential. Our studies have shown that the fungicides captan, mancozeb, tolylfluanid, fenhexamid, cyprodinil + fludioxonil affect N. floridana in a way that may be detrimental to the biocontrol potential of this beneficial fungus in the field. Use of resistant varieties is also important in integrated pest management because pests are known to be more vulnerable to pathogens if they feed on poor or resistant plants and our studies on effects of host plants of spider mites confirms this.

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Three unsprayed coffee farms (farm 1, 2 and 3) were studied for the natural occurrence of the insect pathogenic fungus Beauveria bassiana in Hypothenemus hampei populations throughout the rainy season of 2004 (July-November) and 2005 (July-December). B. bassiana infections were found during most sampling dates in both years, on all three farms. The B. bassiana infection levels were higher in 2005 than in 2004 with mean prevalence of 12.1 % and 2.7%, respectively. No consistent significant differences in infection level between farms were found in any of the years. B. bassiana infection levels fluctuated widely throughout the season, and peaked at 13.5% on farm 3 in 2004 and at 44.0% on farm 1 in 2005. The H. hampei population was significantly higher in 2004 than in 2005, with 6.9% of the berries infested in 2004 and only 0.7% in 2005. In both years, the H. hampei infestation level was significantly higher on farm 2. No consistent significant differences in H. hampei infestation levels were found between sampling dates on any of the farms. H. hampei infestation levels fluctuated throughout both seasons, and peaked at 15.3% on farm 2 in 2004 and 2.2% on farm 2 in 2005. No consistent density dependent correlation between H. hampei infestation level and B. bassiana infection level was found. Correlations between climatic conditions and R bassiana or H. hampei were not found. (C) 2007 Elsevier Inc. All rights reserved.

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Sammendrag

To evaluate overwintering strategies of the fungus Neozygites floridana, an important natural enemy of Tetranychus urticae, hibernating T. urticae females were investigated for the presence of fungal structures throughout one winter (October 12, 2006 to February 19, 2007) in field-grown strawberries in a cold climate in Norway ( min. ambient temp -15.3 degrees C). Neozygites floridana was present as hyphal bodies inside live, hibernating females in T. urticae populations throughout the sampling period. The lowest percentages of hibernating females with hyphal bodies were found at the two first dates of sampling at 5.5 and 0% on October 12 and 19, respectively. The prevalence then increased and peaked at 54.4% on January 14. Resting spores (immature) were also found in live hibernating females at some dates, but at lower prevalence than for hyphal bodies and predominantly only until November 8. Prevalence of resting spores in live hibernating females ranged from 2.5 to 13.8%. Total number of T. urticae was also recorded, and most mites of all four categories (nymphs, males, non-hibernating and hibernating females) were found at the first sampling date. At this date non-hibernating females were the most abundant. A sharp decrease in non-hibernating females, nymphs and males was, however, seen from mid-October to mid-November; also numbers of hibernating females decreased, but not as fast. The relative abundance of hibernating females compared to non-hibernating females increased from 32.2% at the first collection (October 12) to 97.7% at the last collection (February 2). This study confirms that N.floridana survives the winter as a semi-latent hyphal body infection, protected inside live hibernating females. It is therefore ready to develop and sporulate as soon as climatic conditions permit, resulting in early season infection of T. urticae.

Sammendrag

In a pilot field study conducted in an apple orchard in Hardanger (Western Norway) in two succesive years both Beauveria bassiana and Metarhizium anisopliae were applied to apple trees just after hatching of mirid nymphs in spring. Both predatory, omnivorous and principally plant-pathogenic species of mirids were collected, and all groups of species were infected by B. bassiana or M. ansiopliae in treated plots. B. bassiana and M. anisopliae were also found on some individuals in non treated control plots the second year. M. anisopliae was more predominant in 2006, B. bassiana in 2007. Mirids were also observed for natural occurrence of parasitoids, and parasitoids were found both years.

Sammendrag

Four populations of pollen beetle (Meligethes aeneus) was tested for susceptibility to lambda-cyhalotrin and tiacloprid in 2008. Resistance to pyrethroids was found in 2 populations from locations near Hamar, both in field tries and bioassays. One population from Vestfold has low resistance. The results was concistent with what was found in 2007. One population from Østfold had to high control mortality to draw any conclusion. These beetles were collected  very late in the season. Low resistance was found in the same district in 2007. One population from Hamar had lower susceptibility to tiacloprid than the other populations.

Sammendrag

Mulighetene for effektiv bekjempelse av rapsglansbiller er viktig for å gi god økonomi i oljevekstproduksjonen. Fordi det ikke har vært andre godkjente plantevernmidler på markedet, har billene i de siste 10 årene kun blitt bekjempet med pyretroider. Nå har denne ensidige bruken ført til at billene er blitt resistente i flere områder på Østlandet.

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.

Sammendrag

Den middpatogene soppen Neozygites floridana er en viktig naturlig fiende for veksthusspinnmidden, Tetranychus urticae. Plantevernmidler, spesielt soppmidler, kan hemme denne nyttesoppen. Dette bør det tas hensyn til når en sprøyter mot soppsykdommer i jordbær og i andre kulturer hvor veksthusspinnmidden er et problematisk skadedyr. I dette studiet viser vi at soppmidlene Euparen (tolylfluanid), Teldor (fenhexamid) og Switch (cyprodinil +fludioxonil) påvirker N. floridana negativt, mens middmiddelet Mesurol (mercaptodimethur) ikke har noen effekt på denne nyttesoppen. Studiet bekrefter også at soppmiddelet Euparen dreper veksthusspinnmidd.

Sammendrag

Den middpatogene soppen Neozygites floridana er en viktig naturlig fiende for veksthusspinn - midden, Tetranychus urticae. Plantevernmidler, spesielt soppmidler, kan hemme denne nyttesoppen. Dette bør det tas hensyn til når en sprøyter mot soppsykdommer i jordbær og i andre kulturer hvor veksthusspinnmidden er et problematisk skadedyr.

Sammendrag

To obtain information that might help in the use of Neozygites floridana (Zygomycetes: Entomopthorales) in biological control of Tetranychus urticae (Acari: Tetranychidae), in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occur in T. urticae populations in field grown strawberries? 2) How does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) Where do N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to over-winter as hyphal bodies in hibernating T. urticae females throughout the winter. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), results show that the highest numbers of spores (1886 and 1733 per cadaver) were thrown at 13o and 18o compared to 23o C (1302 per cadaver). Spores were thrown at the same distance (up to about 6 mm) at all three temperatures when cadavers were placed with dorsal side facing up. Cadavers placed with dorsal side down (hanging) threw equal numbers of spores up (on the underside of the leaf in nature) and down (on the leaf below). The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempt to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.

Sammendrag

To obtain information that might help in the use of Neozygites floridana (Zygomycetes: Entomopthorales) in biological control of Tetranychus urticae (Acari: Tetranychidae), in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occur in T. urticae populations in field grown strawberries? 2) How does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) Where do N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to over-winter as hyphal bodies in hibernating T. urticae females throughout the winter. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), results show that the highest numbers of spores (1886 and 1733 per cadaver) were thrown at 13o and 18o compared to 23o C (1302 per cadaver). Spores were thrown at the same distance (up to about 6 mm) at all three temperatures when cadavers were placed with dorsal side facing up. Cadavers placed with dorsal side down (hanging) threw equal numbers of spores up (on the underside of the leaf in nature) and down (on the leaf below). The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempt to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.

Sammendrag

Nyttesoppen Neozygites floridana er en viktig naturlig fiende til veksthusspinnmidd. Plantevernmidler, spesielt soppmidler kan hemme denne nyttesoppen. Dette bør det tas hensyn til når en sprøyter mot soppsykdommer i jordbær og i andre kulturer der denne spinnmidden err et problematisk skadedyr.

Sammendrag

Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest for the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occurre in T. urticae populations in fieldgrown strawberries? 2) How and where does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) How and where does N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to overwinter as both hyphal bodies in hibernating T. urticae females from October to at least February at temperatures as low as -20o C. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), preliminary results show that high numbers of spores (ca 1300-1900 per cadaver) were thrown at all three temperatures. Further, spores were thrown about the same distance (up to about 6 mm) at all three temperatures. The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempts to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.

Sammendrag

Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. The fungus is therefore of interest for the biological control of T. urticae. To obtain information that might help in the use of this fungus under practical conditions in strawberries and cucumbers we have tried to answer the following questions in a series of studies*): 1) When, and at what infection levels does N. floridana occurre in T. urticae populations in fieldgrown strawberries? 2) How and where does N. floridana survive harsh climatic conditions (i.e winter) in Norway? 3) How and where does N. floridana infected T. urticae move and sporulate on a plant? 4) How do commonly used pesticides in strawberries affect N. floridana and T. urticae? 5) How can N. floridana be inoculated in augmentative microbial control of T. urticae? Results show that N. floridana infected and killed T. urticae in 12 out of 12 Norwegian strawberry fields studied. Infection levels up to 90% were observed, and the highest levels were observed late in the season. The infection levels throughout a season varied considerably. N. floridana was observed to overwinter as both hyphal bodies in hibernating T. urticae females from October to at least February at temperatures as low as -20o C. Cadavers with resting spores were found from October to the end of January. Cadavers then probably disintegrated, and resting spores were left on leaves, soil, etc. In a bioassay where a Norwegian N. floridana isolate was tested for numbers and distance of spores thrown at three different temperatures (13o, 18o, 23o C), preliminary results show that high numbers of spores (ca 1300-1900 per cadaver) were thrown at all three temperatures. Further, spores were thrown about the same distance (up to about 6 mm) at all three temperatures. The effects of pesticides used in strawberries on the N. floridana infection level were studied to evaluate factors that might be important for conservation biological control. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide/ insecticide: Mesurol (methiocarb). The experiment indicated that all three fungicides affect N. floridana negatively but that Euparen might be the least harmful. Mesurol did not affect N. floridana. Our attempts to inoculate N. floridana artificially in a strawberry field has not yet been successful, but we now work on promising methods for inoculation of N. floridana in T. urticae populations in greenhouse cucumbers. More detailed results from the studies referred to in this abstract will soon be published elsewhere.

Sammendrag

Neozygites floridana is an important natural enemy of the two-spotted spider mite, Tetranychus urticae. Pesticides used in strawberries that might affect the conservation and enhancement of this beneficial fungus were therefore studied. This was done in a laboratory study by letting non-inoculated (healthy) mites and mites inoculated with N. floridana feed on strawberry leaf disks treated with one of the following pesticides: the fungicides tolylfluanid, fenhexamid or cyprodinil + fludioxonil or the acaricide/insecticide/molluscicide methiocarb. The effect of these pesticides on mortality and egg production of T. urticae and on the killing capacity and sporulation of N. floridana were determined. Tolylfluanid increased the mortality of non-inoculated mites (75.3%) compared to the non-inoculated control (27.5%). Methiocarb also killed non-inoculated mites. Fenhexamid did not have any effect on the mortality of non-inoculated mites (19.2%), neither had cyprodinil + fludioxonil (19.1%). Tolylfluanid did not reduce the mortality of mites inoculated with N. floridana (89.3%) compared to the inoculated control (80.0%). Neither did methiocarb, it rather increased the mortality of inoculated mites (93.2%). Fenhexamid did, however, reduce the mortality of inoculated mites (66.7%). The same was true for cyprodinil + fludioxonil (48.7%). In addition, cyprodinil + fludioxonil increased the time to death of inoculated mites (6.69 days) compared to the control (6.10 days), and inhibited sporulation of N. floridana (7.9% sporulation) compared to the control (42.4% sporulation). Tolylfluanid also reduced sporulation of N. floridana (15.5% sporulation). Results from this study indicate that the use of the fungicides tested will potentially reduce the survival and efficacy of the natural enemy N. floridana in the field.

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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.

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Methods for measuring prevalence of Neozygites floridana in a Tetranychus urticae population collected from strawberries were developed and compared. T. urticae were extracted from leaves using a soapy water solution (0.5 ml washing detergent : 8 l water) and then placed into 80% alcohol for use in methods 1 and 2. Method 1: N. floridana-sporulating T. urticae cadavers were observed and quantified under a compound microscope (40-80X). Method 2: Adult females were mounted in lactophenol cotton blue and observed for the presence or absence of N. floridana hyphal bodies under a microscope (200-400X). Method 3: Live T. urticae females were incubated at 25ºC and 75% RH and observed for mortality and N. floridana infection under a compound microscope (6.4-40X). Method 1 was the most time-efficient method and it also allows processing of samples as time permits. Method 2 quantified significantly higher fungal prevalence than method 1 and 3, but method 2 is not considered to be reliable because hyphal bodies are difficult to detect. No significant differences were found between methods 1 and 3.

Sammendrag

Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. In a study conducted in Norwegian strawberry fields, N. floridana infected and killed T. urticae in all 12 fields studied. Infections up to 90% were registered, and the highest infection levels were observed late in the season. The infection levels throughout a season varied considerably. To evaluate factors that might be important for conservational biological control, the effect of pesticides used in strawberries on the N. floridana infection level were also studied. The pesticides tested were three fungicides; Euparen (tolylfluanid), Teldor (fenhexamid), Switch (cyprodinil +fludioxonil) and one acaricide: Mesurol (mercaptodimethur). The experiment indicates that Euparen and Switch do not affect the N. floridana killing capacity, but both Teldor and Mesurol do. Methods for the production and storage of N. floridana infected T. urticae cadavers for inoculative/ inundative biological control in strawberries were established in our laboratory and are presented briefly in this paper. Similar methods might be adapted for the inoculative/ inundative biological control of T. urticae in for example greenhouse crops.

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In a survey in one conventional and four organic apple orchards in southeast Norway insect pathogenic fungi and parasitoids as natural enemies of green apple aphid (Aphis pomi) and rosy apple aphid (Dysaphis plantaginea) were studied weekly throughout the summer 2002 and 2003. Four species of insect pathogenic fungi in the order Entomophthorales were observed to infect both aphid species. These were Entomophthora planchoniana, Neozygites fresenii, Erynia neoaphidis and Conidiobolus obscurus. The highest fungal infection level in A. pomi was 39,6 % and 33,3 % in D. plantaginea. Neozygites fresenii was the fungal species being the most prevalent. This fungus also seemed to cause an epizootic in A. pomi and to decrease the aphid population in one organic location during the summer 2002. Parasitoids were a more important mortality factor in A. pomi than in D. plantaginea, and the highest parasitization recorded in A. pomi was 30 %. Four species of primary parasitoids hatched from A. pomi: Binodoxys angelicae, Lipolexis gracilis, Praon sp. and Ephedrus sp. Hyperparasitoids that hatched from A. pomi were Dendrocerus carpenteri, Alloxysta pleuralis, Phaenoglyphis villosa and Asaphes suspensus. Only one individual of D. plantaginea was parasitized and this parasitoid was Ephedrus persicae. Both fungi and parasitoids were abundant early in the season. The fungi were found from late June and throughout the season in some locations in 2002. Resting spores of N. fresenii were found in A. pomi in July. The parasitization showed two tops, one early in season (June/July) and one late in season July/August. Fungal infections were more prevalent than parasitoids in D. plantaginea. Fungi and parasitoids were equally important in A. pomi.

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Insect pathogenic fungi and parasitoids are important control agents of aphids. In a survey in one conventional and four organic apple orchards in Norway insect pathogenic fungi and parasitoids as natural enemies of Aphis pomi and Dysaphis plantaginea were studied weekly in the summer 2002 and 2003. Four species of insect pathogenic fungi in the order Entomophthorales were observed in both apple aphid species: Entomophthora planchoniana, Neozygites fresenii, Erynia neoaphidis and Conidiobolus obscurus. The fungus N. fresenii caused an epizootic on A. pomi in one organic location and seemed to decrease the aphid population during the summer 2002. The highest mortality caused by fungal infection of A. pomi was 39,6 % and 33,3 % of D. plantaginea. Mortality caused by parasitoids was more important in A. pomi than in D. plantaginea and the highest parasitation recorded in A. pomi was 30 %. Four species of primary parasitoids hatched from A. pomi: Binodoxys angelicae, Lipolexis gracilis, Praon sp. and Ephedrus sp. Hyperparasitoids that hatched from A. pomi were: Dendrocerus carpenteri, Alloxysta pleuralis, Phaenoglyphis villosa and Asaphes suspensus. Only one individual of D. plantaginea was parasitized and this parasitoid was Ephedrus persicae.

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In coffee systems, shade management and pests control practices are related to the occurrence of arthropods and micro-organisms, because such practices alter the environmental conditions in the system. The insect pathogenic fungi Beauveria bassiana is used as a microbial control agent against coffee berry borer Hypothenemus hampei, in several countries in America, and it has also been reported to infect the coffee leaf miner Leucoptera coffeella. Only few studies have, however, focused on the natural infection level and the effect of shade and pest management on the dynamic of B. bassiana or other insect pathogenic fungi on key coffee pests. Understanding the dynamic of B. bassiana in the field and its genetic diversity is very important not only to favour its natural occurrence and enhance the natural control, but also to select strains with a good field performance and virulence. The main objectives of this PhD study conducted in Nicaragua are therefore to: a) determine the natural occurrence and infection level of B. bassiana on H. hampei and L. coffeella in unsprayed coffee plantations throughout two successive seasons; b) clarify whether B. bassiana is present as an endophyte in coffee trees, and determine whether B. bassiana injected into coffee plants can establish and persist; c) reveal the effect of shade and use of pesticides on insect pathogenic fungi on H. hampei and in the soil, and d) compare B. bassiana isolates obtained from L. coffeella, H. hampei and the soil at the same and different locations by the use of PCR techniques. The research is being carried out over a period of two years, 2004 and 2005. The natural occurrence and infection level of B. bassiana and the study on endophytic B. bassiana will be studied in unsprayed coffee plantations in the north and the pacific zone of Nicaragua. The experiment on the effect of shade and management practices will be carried out in plots with different pest management practices already established by CATIE in Masatepe, Nicaragua.

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- Insect pathogenic fungi are important naturally occurring mortality factors of pest insects and mites. - Few studies have been made on natural occurrence of insect pathogenic fungi and the effect of management system in Central America. - One study from Norway confirms that management system (organic compared to conventional) is important to the occurrence and prevalence of insect pathogenic fungi in soil in arable fields. - Another study from Norway indicates the importance of pesticide use on the killing capacity of the mite pathogenic fungi N. floridana to T. urticae. - A master study from Nicaragua showed a higher B. bassiana infection level in L. coffeella with increasing shading. More studies are, however, needed to confirm this trend. - In a PhD project at CATIE Nicaragua, naturally occurring insect pathogenic fungi on key coffee pests and the effect of crop management practices on these fungi is under study. - An ongoing master study will reveal the occurrence of insect pathogenic fungi in soil from different coffee growing systems in Nicaragua and Costa Rica.

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Both insect pathogenic fungi and parasitoids are important for the regulation of insect pests in organic and integrated fruit production. In perennial crop systems, where the pest spends significant periods of time in permanent habitats, biological control is often successful. This is in part due to the stable and robust perennial ecosystem that acts as a reservoir for insect pathogens, parasitoids and other natural enemies of pests. Black cherry aphid (Myzus cerasi) is one of the most important pests on cherries all over the world. However, there are few studies on M. cerasi and insect pathogenic fungi. In this study the occurrence and importance of insect pathogenic fungi and parasitoids as natural enemies of the black cherry aphid was investigated throughout two successive seasons in Norway. Results show that in the first part of the season, from the last part of May to mid July, mostly parasitoids were found in dead aphids. Parasitoids of the following species were found: Ephedrus plagiator and E. persicae. The hyperparasitoids Alloxystra victrix and Dendrocerus sp. were also found in this part of the season, and a few individuals infected with fungi in the order Hyphomycetes (Verticillium lecanii). From the middle of July, fungi in the order Entomophthorales (Entomphthora planchoniana, Erynia neoaphidis and Conidiobolus obscurus) were found in dead aphids. Number of aphids killed by fungi increased towards the end of July. There was, however, a big variation in infection level between trees.

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Neozygites floridana is a fungus in the order Entomophthorales that infects and kills the two-spotted spider mite, Tetranychus urticae. N. floridana is the key regulator factor of T. urticae on maize and soybean in the mid-western and south-eastern USA where farmers are encouraged to adapt their fungicide spray programmes to avoid suppressing the fungus (Cross et al. 1999). To our knowledge few systematic studies have been conducted on N. floridana as a mortality factor of T. urticae in strawberry fields. Some preliminary studies have, however, been conducted in Poland which indicate that N. floridana might be important for the regulation of T. urticae in strawberry. A cropping system that enhances the prevalence of N. floridana might therefore be important for the reduction of T. urticae in strawberry. In our studies we therefore aim to clarify the effect of different strawberry growing systems on the infection level of N. floridana. In one study, the occurrence of N. floridana in T. urticae in organic and conventional strawberry fields was studied in the summer 2002 and 2003. Strawberry leaves were collected from two fields, one organic and one conventional, from each of six different locations in Norway (Lier, Follo, Evje, Finnskog, Kise, Toten). Leaf samples were collected at four-weekly intervals. First sampling was conducted in June/July and the second in July/August. Preliminary results show that N. floridana infected and killed T. urticae in all strawberry fields studied. Infections from 0 to 19% were registered, and the highest infection rates were observed late in the season from the second sampling. Our preliminary results do not show any relationship between occurrence of N. floridana and strawberry cropping systems. The fluctuation in the N. floridana infection rate throughout the season might be higher than observed in the first study. A second study on the infection level of N. floridana in a T. urticae population throughout the season 2003 was therefore conducted in a conventional strawberry field in Follo. Our preliminary results show that the highest N. floridana infection level for this field was around 20%.

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Bladlus fra familien Aphididae er blant de viktigste skadedyrene i jord og hagebruk i den tempererte klimatiske sonen. De bekjempes hovedsakelig ved bruk av kjemiske insektmidler, men både insektpatogene sopp og parasitoider (insekt parasitter) er viktige for den naturlige kontrollen av bladlus. I et studie ved Planteforsk undersøkes derfor forekomsten og viktigheten av insektpatogene sopper og parasitoider som naturlig fiende til kirsebærbladlus (Myzus cerasi). Foreløpige resultater viser at det for det meste var parasitoider som drepte bladlusa tidlig i sesongen (opptil 30%). Noen få kirsebærbladlus med den insektpatogene soppen Verticillium lecanii ble også funnet tidlig i sesongen. Fra midten av juli ble et betydelig antall kirsebærbladlus (opptil 50%) infisert og drept av insektpatogene sopper innen ordenen Entomophthorales (Entomophthora planchoniana, Erynia neoaphidis og Conidiobolus obscurus). Antall soppdrepte bladlus så ut til å øke mot slutten av juli. I et annet studie ved Planteforsk undersøkes det om bruk av soppmidler og dekking av kirsebærtrærne har effekt på kirsebærbladluspopulasjonen og soppene som dreper kirsebærbladlusa. Foreløpige resultater viser at kirsebærtrær som ikke er dekket mot regn og som ikke behandles med soppmidler muligens kan få en reduksjon i kirsebærbladluspopulasjonen mot slutten av sesongen. Effekten av dekking og soppmidler på soppene som dreper kirsebærbladlusa er enda ikke evaluert.

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Det er ikke bare mykhorriza som hører til blant de snille soppene (sv. svamp) i økologisk landbruk. Også sopper som dreper skadedyr må regnes med blant våre viktige venner

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Neozygites floridana er en sopp innen orden Entomophthorales som infiserer og dreper veksthusspinnmidd (Tetranychus urticae). Forekomsten av N. floridana i veksthusspinnmidd i økologiske og konvensjonelle jordbærfelt ble undersøkt sommeren 2002. Jordbærblader ble samlet inn fra to felt, ett økologisk og ett konvensjonelt, fra hver av 6 lokaliteter i Norge (Lier, Follo, Evje, Finnskog, Kise, Toten). Innsamlingen ble foretatt to ganger med fire ukers mellomrom. En gang i overgangen juni/ juli og en gang i juli/ august. Foreløpige resultater viser at N. floridana infiserte og drepte veksthusspinnmidd i jordbær i alle undersøkte felt, med unntak av ett konvensjonelt jordbærfeltet i Lier. Infeksjonsprosenter fra rundt 0 til 19% ble registrert, og de høyeste infeksjonsprosentene ble observert sent på sesongen, det vil si ved den andre prøvetakningen. Svingningen i infeksjonsprosenten gjennom sesongen kan imidlertid ha vært betydelig større, og det tas sikte på å studere dette nærmere senere i prosjektet. Slik resultatene foreligger i dag kan vi ikke vise noen sammenheng mellom forekomst av N. floridana og dyrkningssystem i jordbær.

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A checklist of naturally occurring microbes and nematodes that are pathogenic to insects and mites in Norway is presented. All records are listed by pathogen group (fungi, bacteria, viruses, and nematodes). Each record is listed with reference to the original author, and subsequent references have been included. The checklist should be updated periodically to assist researchers and policy makers within the field of entomology and crop protection.

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Studies were conducted to investigate potential interactions between brassicaceous plants, the isothiocyanates they produce and insect pathogenic fungi. Studies in vitro showed that 100 ppm of 2-phenylethyl isothiocyanate completely inhibited growth of Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was significantly inhibited by 10 ppm 2-phenylethyl isothiocyanate, but not by 1 ppm. M. anisopliae was not inhibited by 10 or 1 ppm 2-phenylethyl isothiocyanate. The effect of freshly grated rutabaga on virulence of M. anisopliae to Galleria mellonella larvae was also tested, resulting in reduced infection by M. anisopliae. To study the effect of plants in the Brassicaceae under more field-like conditions fungi were added to soil without plants or at the bases of two different plant species, Barbarea vulgaris and Eruca vesicaria sativa. Soil was sampled at 5, 10 and 15 days to determine the concentration of colony forming units (CFUs). Treatments with plants did not have fewer CFUs than the control. Instead significantly fewer CFUs resulted when M. anisopliae was added to pots with soil only than to pots with plants. There were no significant differences between the two plant species in the number of CFUs at day 5. For days 10 and 15, however, significantly more M. anisopliae CFUs were found in pots containing E. vesicaria sativa than B. vulgaris. T. cylindrosporum was less affected by the different treatments than M. anisopliae. Our studies demonstrated that while isothiocyanates can inhibit insect pathogenic fungi in Petri dishes, when using a more realistic fungus/plant/soil microcosm no fungal inhibition was found.

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A method for baiting soil samples with Delia floralis larvae was developed, and a systematic survey was conducted on soils from northern Norway for insect pathogenic fungi, using D. floralis and Galleria mellonella larvae as bait. The occurrence of insect pathogenic fungi in soils from arable fields and adjacent field margins of conventionally and organically managed farms was compared. The study showed a significantly higher occurrence of insect pathogenic fungi in soils from arable fields of organically managed farms. No significant differences in the occurrence of insect pathogenic fungi were, however, found between the field margins of the two cropping systems. Fungal species identified in the study were Beauveria bassiana, Fusarium merismoides, Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was found more frequently when using D. floralis as the bait insect than when using G. mellonella.

Sammendrag

Både insektpatogene sopper og parasitoider er viktige for reguleringen av skadedyr i økologisk og integrert fruktproduksjon. To studier ble gjennomført for å klargjøre biologien til dette komplekset av naturlige fiender og for å undersøke mulighetene for å bruke insektpatogen sopp i biologisk kontroll av kirsebærbladlusa (Myzus cerasi). Foreløpige resultater presenteres i denne artikkelen. I den første undersøkelsen ble forekomsten og viktigheten av insektpatogene sopper og parasitoider som naturlige fiender til M. cerasi undersøk gjennom to påfølgende sesonger. Foreløpige resultater viser at tidlig i sesongen er det først og fremst parasitoider som blir funnet i døde bladlus. Noen få individer infisert med sopp fra klasse Hyphomycetes (Verticillium lecanii) ble også funnet i denne delen av sesongen. Fra midten av juli ble sopp fra orden Entomophthorales (Entomphthora planchoniana, Erynia neoaphidis and Conidiobolus obscurus) funnet i døde bladlus. Antall bladlus drept av sopp ser ut til å øke mot slutten av juli. I studie nummer to ble effekten av soppmidler or dekking mot regn på insektpatogene sopp og tettheten av M. cerasi undersøkt. Foreløpige resultater fra dette studiet indikerer at søtkirsebærtrær som ikke dekkes og som ikke behandles med soppmidler muligens gir et brattere fall i M. cerasi tettheten mot slutten av sesongen. Effekten av soppmidler og dekking mot regn på M. cerasi drept av insektpatogene sopper har ikke blitt evaluert enda.

Sammendrag

The susceptibility of Delia floralis eggs, neonates and larvae and the susceptibility of Galleria mellonella and Mamestra brassicae larvae to seven different Norwegian isolates of the insect pathogenic, hyphomycetous fungi Tolypocladium cylindrosporum, Metarhizium anisopliae and Beauveria bassiana, were investigated. Metarhizium anisopliae isolate ARSEF 5520 was highly virulent to G. mellonella larvae and caused 100% mortality when tested at a concentration of 3.6x106 conidia/ml. The same M. anisopliae isolate was not virulent to D. floralis larvae. Isolates of T. cylindrosporum, were equally virulent to G. mellonella and D. floralis causing up to 36.0% mortality of larvae. It is suspected, however, that the use of grated rutabaga as a food source in the D. floralis bioassay reduced the fungal virulence of both M. anisopliae and T. cylindrosporum to D. floralis. Among three T. cylindrosporum isolates tested at a concentration of 1.0x107 against eggs of D. floralis none of them reduced the hatching percentage. One isolate, ARSEF 5525 did, however, significantly reduce the longevity of neonates. Beauveria bassiana isolates ARSEF 5510 and ARSEF 5370 tested at a concentration of 1.0x107resulted in M. brassicae mortality levels of 70.0 and 55.0% respectively. The B. bassiana isolate ARSEF 5557, however, was not virulent to M. brassicae. Among the three isolates tested against M. brassicae the two virulent isolates produced a red pigment, probably oosporein, when cultured in Sabouraud dextrose agar.

Sammendrag

I et nytt prosjekt under innsatsområdet økologisk landbruk ved Planteforsk undersøkes forekomsten og viktigheten av insektpatogene sopp og virus som naturlig fiende til skadedyr i norske frukthager. Ideen er at bruk av nyttemikrober til regulering av skadedyrpopulasjoner vil kunne bli viktig både i økologisk og integrert fruktdyrkning. Videre egner flerårige kulturer som frukt seg meget godt for mikrobiologisk bekjempelse av skadedyr fordi en da har anledning til å utnytte et stabilt og robust økosystem hvor insekt- og middpatogener kan være med på å holde skadedyrpopulasjonene nede. Arbeidet med prosjektet ble startet i februar 2001, og skadedyrene og patogenene vi har konsentrert oss om i 2001 er sopp på kirsebærbladlus (Mysus cerasi) og virus og sopp på liten frostmåler (Operopthera brumata) og bølgefly (Eupsilia transversa). Foreløpige resultater viser at flere insektpatogene sopper fungerer som naturlige fiender for kirsebærbladlus, men at det i 2001 var lite virus å finne i larver av frostmåler og bølgefly. Videre gjøres det i disse dager  undersøkelser hvor en sammenlikner forekomsten av insektpatogene sopp i jord fra økologiske kontra konvensjonelle eplehager i Sogn.

Sammendrag

Sopp kan infisere og drepe insekter. Disse insektpatogene soppene er ofte små og uanselige, men kan likevel føre til stor dødelighet. Når de opptrer epidemisk gjør de rent bord, og betyr mye for reguleringen av insektpopulasjoner. Sammen med predatorer, insektparasitter og ikke-biologiske faktorer er insektpatogener avgjørende for svingninger i insektpopulasjoner i både naturlige og påvirkede økosystemer. Insektpatogene sopper kan også brukes til bekjempelse av skadeinsekter. Dett er et fascinerende alternativ til kjemisk bekjempelse av skadedyr og naturens egne utspekulerte strategier tas i bruk.

Sammendrag

Brassiceye® traps baited with ethylisothiocyanate were modified and used to collect adults of Delia radicum and D. floralis from the field to observe the infection level of Entomophthora muscae and Strongwellsea castrans. This study confirms that both E. muscae and S. castrans contain the basic properties to establish epidemics and act as important mortality factors in the field. Our results also suggest that E. muscae dominates under warm conditions and that S. castrans might be more dominating under cold conditions. The study also indicates that modified Brassiceye® traps are effective and very selective for D. radicum and D. floralis. Advantages and disadvantages of using different capture methods for fly population monitoring, pathogen sampling, and autodissemination are presented.

Sammendrag

In a series of studies (Papers I-IV), insect pathogenic fungi from Norway were collected and mapped to evaluate their importance as natural control factors and their potential as microbial control agents against pest insects in Brassica vegetables. An overview of known pathogens of arthropods in Norway is also provided (Paper V).By quantifying the seasonal infection levels of Entomophthora muscae and Strongwellsea castrans in a population of adult Delia radicum and Delia floralis it was revealed that S. castrans and particularly E. muscae cause high levels of mortality. Conservation and enhancement of these fungi have a potential in the control of the flies. Traps modified during the study and used to collect live adults of D. radicum and D. floralis were highly effective and selective and might be used to spread insect pathogens to control the flies.In a survey conducted in northern Norway to isolate insect pathogenic fungi from soil, more insect pathogenic fungi were found in arable fields of organically farmed soil compared to arable fields of conventionally farmed soil. Tolypocladium cylindrosporum was found more frequently when using D. floralis larvae as the bait insect than when using Galleria mellonella.In vitro studies show that 2"phenylethyl isothiocyanate inhibits the growth of both Metarhizium anisopliae and T. cylindrosporum. The effect was more pronounced for T. cylindrosporum. M. anisopliae treated G. mellonella larvae exposed to grated rutabaga resulted in lower infection by M. anisopliae. The effect of plants in the Brassicaceae was also studied in a fungi/plant/soil experiment, but roots of Beta vulgaris and Eruca vesicaria sativa do not seem to have a negative effect on the M. anisopliae and T. cylindrosporum isolates applied to the soil at the bases of the plants. Results obtained on the virulence of Norwegian hyphomycetous isolates to immature stages of D. radicum and D. floralis did not result in a selection of an isolate for further development. Promising results were, however, obtained for Norwegian Beauveria bassiana isolates tested against second instar larvae of Mamestra brassica resulting in mortality up to 70%. Several isolates should be further evaluated as potential microbial control agents

Sammendrag

The coffee leaf miner Leucoptera coffeella (Lepidoptera: Lyonetiidae) is one of the most important coffee pests in Lathin America. Larvae of L. coffeella were collected at 10 different locations in a coffee growing region in Nicaragua to study the natural occurrence of insect pathogenic hyphomycetous fungi. The study reveals that Beauveria bassiana (Deuteromycotina: Hyphomycetes) might be a natural mortality factor for L. coffeella larvae, and a B. bassiana infection level up to 22.1 % was observed. To our knowledge, this is the first study estimating the B. bassiana infection level in L. coffeella, and also one of the first reports on B. bassiana associated with this insect. Significant and positive correlations with B. bassiana infection level in L. coffeella larvae were observed for factors related to high L. coffeella densities, and the coffee variety "Catrenic" showed a significant higher L. coffeella density as well as a higher B. bassiana infection level than the other coffee varieties. A tendency towards higher B. bassiana infection level with increasing shading was also observed. Copper was applied as a fungicide at some of the locations, but did not seem to negatively affect the B. bassiana infection level as much as other fungicides. In this study coffee leaves were also examined for endophytic B. bassiana, but no such association was found. 

Sammendrag

Ny forskning viser at skadedyr som kålfluer kan bekjempes ved hjelp av naturens egne metoder: enkelte sopparter kan på en "utspekulert" måte drepe fluene - samt spre smitten videre.

Sammendrag

Biodiversity studies of insect pathogenic fungi are normally conducted by the use of Galleria mellonella (Lepidoptera) or Tenebrio molitor (Coleoptera) as bait insects. These insects are easy to obtain and handle and large numbers of fungal isolates are often obtained by the use of these standard bait insects, but they usually yield only a limited number of fungal species.  It was therefore an aim to compare the standard bait insect G. mellonella with Delia floralis (Diptera), a soil dwelling pest of Brassica vegetables, as bait insect. A method for baiting soil samples with D. floralis larvae was developed, and a systematic survey was conducted on soils from northern Norway for insect pathogenic fungi. Fungal species identified in the study were Beauveria bassiana, Fusarium merismoides, Metarhizium anisopliae and Tolypocladium cylindrosporum. T. cylindrosporum was found more frequently when using D.  floralis as the bait insect than when using G. mellonella. Comparisons between the occurrences of insect pathogenic fungi in organically versus conventionally farmed soil have so far only been undertaken on a minor scale. This study therefore also aimed to compare the abundance of insect pathogenic fungi in organically and conventionally farmed soil and in soil from arable fields and the adjacent semi-natural field margins.  The study showed a significantly higher occurrence of insect pathogenic fungi in soils from arable fields of organically managed farms. No significant differences in the occurrence of insect pathogenic fungi were, however, found between the field margins of the two cropping systems.

Sammendrag

I norsk fruktdyrking legges det vekt på nyttedyr som naturlige reguleringsmekanismer for skadedyr (insekter og midd). Naturlig forekommende patogener utgjør imidlertid også en viktig dødelighetsfaktor for mange skadedyr, og funn gjort både i Norge og utlandet peker i retning av at nyttemikrober bør få en viktigere plass i både integrert og økologisk fruktdyrking.

Sammendrag

Naturlig forekommende insekt- og middpatogener kan være en viktig dødelighetsfaktor for mange skadedyr. Funn gjort både i Norge og utlandet peker i retning av at nyttemikrober bør få en viktigere plass i både integrert og økologisk fruktdyrkning.

Sammendrag

Brassiceye traps baited with ethylisothiocyanate were modified and used to collect live adults of Delia radicum (L.) and Delia floralis (Fallén) (Diptera: Anthomyiidae) from the field to observe the prevalence of Entomophthora muscae (Cohn) Fresenius and Strongwellsea castrans Batko & Weiser. The traps were highly effective and selective for D. radicum and D. floralis. Of the flies identified, 98.4% in 1996 and 93.7% in 1997 were either D. radicum or D. floralis. In 1997 the maximum mean catch was as high as 82 flies per trap per day, and more than 80% of these were females. During both seasons E. muscae caused relatively high levels of mortality in adult populations of D. radicum and D. floralis. The fungus caused a total infection level of 17.9% in 1996 and 47.7% in 1997 with infection peaks of 82.4% in 1996 and 87.5% in 1997. Both years, a significant positive correlation was found between E. muscae prevalence and temperature. One infection peak was observed for S. castrans in 1996, and during that season the total S. castrans infection level was 18.0%. In 1997, the total S. castrans infection level was as low as 8.1%. There is no strong indication that the prevalence of E. muscae or S. castrans differs between either the fly species or sexes within species.

Sammendrag

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.