E nema GmbH

Schwentinental, Germany

E nema GmbH

Schwentinental, Germany
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Toepfer S.,CABI Europe Switzerland | Burger R.,LANDI Reba AG | Ehlers R.-U.,University of Kiel | Peters A.,E nema GmbH | Kuhlmann U.,CABI Europe Switzerland
Journal of Applied Entomology | Year: 2010

The three larval instars of western corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) feed on the roots of maize, Zea mays (L.). The effects of six application techniques on the plant-scale efficacy of the entomopathogenic nematode species, Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), in controlling D. v. virgifera populations were assessed in seven field plot experiments in southern Hungary between 2004 and 2007. Approximately 230 000 nematodes were applied per row metre using four different stream spray techniques; or, alternatively 400 000 nematodes per square metre using two different flat spray techniques. Nematode efficacy was assessed by comparing the number of emerging adult D. v. virgifera, and root damage between treatments and untreated controls. All tested nematode application techniques reduced D. v. virgifera density by at least 50% (on average across fields and years). The highest reduction in D. v. virgifera density was 68% and occurred when nematodes were applied into the soil together with maize sowing using a fluid solid stream. Rainfall, the day before application likely increased the control efficacy of H. bacteriophora. Using the 0.00-3.00 node injury damage rating scale, we estimated that potential root damage was prevented by 25-79% when H. bacteriophora was applied. Although, H. bacteriophora can effectively be applied with all of the techniques tested, for optimum performance and minimum costs, it is suggested that the nematodes be applied as follows: (i) as a stream requiring 8-10 times less volume of water than flat sprays, or as a granule requiring no water, and (ii) into the soil when sowing maize, requiring less water than soil surface sprays and avoiding the destruction of nematodes by UV radiation and additional machinery use. © 2009 Blackwell Verlag, GmbH.

Iqbal M.,Ghent University | Ehlers R.-U.,E nema GmbH | Waeyenberge L.,Belgium Institute for Agricultural and Fisheries Research
Nematology | Year: 2016

Entomopathogenic nematodes belong to the families of Steinernematidae and Heterorhabditidae. They are obligate and lethal parasites of insects that can provide effective control of some important pests of commercial crops. A total of 53 isolates of EPN were molecularly characterised (ITS region-based) in the present study. Most of the studied isolates belong to the Steinernema genus and only few isolates belong to the Heterorhabditis genus. The phylogenetic relations of Steinernema and Heterorhabditis species were analysed by utilising the maximum likelihood method. In the Steinernema phylogenetic tree, 99 isolates formed five major, moderately or highly reinforced clades: clade I: affine-intermedium group; clade II: carpocapsae-siamkayai-tami-scapterisci; clade III: bicornutum-riobrave-thermophilum; clade IV: glaseri-arenarium-karii-longicaudum; and clade V: feltiae-schliemanni-kushidaikraussei- oregonense. The BLAST analysis of the ITS region of the rDNA of the steinernematid isolate PAL10 showed a rather low similarity of 93% with S. vulcanicum (accession number: GU929442), supporting the possible designation of a new species. In the Heterorhabditis phylogenetic tree, 25 isolates formed three main clades: clade I: bacteriophora-argentinensis-hepialius; clade II: baujardi-sonorensis-amazonensis; and clade III: indica-brevicaudis-hawaiiensis. All five studied isolates of Heterorhabditis were identified as H. indica and H. bacteriophora. In both phylogenetic trees, the intra-specific variability level was different among clades for some species. The description of the new species (PAL10 isolate) would need further morphometric characterisation, morphologically identification and cross-breeding studies. © Koninklijke Brill NV, Leiden, 2016.

Toepfer S.,Directorate for Plant Protection and Soil Conservation | Hatala-Zseller I.,Directorate for Plant Protection and Soil Conservation | Ehlers R.-U.,University of Kiel | Peters A.,E nema GmbH | Kuhlmann U.,CABI Europe Switzerland
Agricultural and Forest Entomology | Year: 2010

1 Field studies on the efficacy of entomopathogenic nematodes as biological pest control agents in field crops and over multiple seasons are rare. 2 In the present study, we investigated the efficacy of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) at reducing maize root damage caused by the larvae of the western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae). The study consisted of 21 field-scale experiments in Hungary conducted between 2004 and 2007. Key factors behind successful control, such as application techniques, nematode dosage, soil environment and rainfall, were analyzed. 3 Five of the six tested techniques for applying the nematodes using readily available farming machinery resulted in a reduction of root damage, as well as subsequent plant lodging. 4 According to damage rating with the Iowa 1-6 scale, damage was reduced by 3-18%. According to the 0.00-3.00 node injury scale, damage was reduced by 14-54%. Approximately 7-62 % of plant lodging, and thus direct yield losses as a result of in-harvestability, was prevented. 5 An increase in nematode dosage and/or an increased rainfall during the period of applications increased the efficacy of H. bacteriophora at reducing root damage. Except for the obvious effect of moisture, the soil environment had little measurable influence on nematode efficacy. 6 The present study demonstrates the potential for field-scale nematode application to significantly reduce damage caused by D. v. virgifera larvae. It is recommended that the method of agent application should be selected on a case-by-case basis considering the efficacy data presented here, the available application machinery and its associated costs. © 2010 The Authors. Agricultural and Forest Entomology © 2010 The Royal Entomological Society.

Perry R.N.,Rothamsted Research | Ehlers R.-U.,E nema GmbH | Glazer I.,Institute of Plant Protection
Journal of Nematology | Year: 2012

Understanding the desiccation survival attributes of infective juveniles of entomopathogenic nematodes (EPN) of the genera Steinernema and Heterorhabditis, is central to evaluating the reality of enhancing the shelf-life and field persistence of commercial formulations. Early work on the structural and physiological aspects of desiccation survival focused on the role of the molted cuticle in controlling the rate of water loss and the importance of energy reserves, particularly neutral lipids. The accumulation of trehalose was also found to enhance desiccation survival. Isolation of natural populations that can survive harsh environments, such as deserts, indicated that some populations have enhanced abilities to survive desiccation. However, survival abilities of EPN are limited compared with those of some species of plant-parasitic nematodes inhabiting aerial parts of plants. Research on EPN stress tolerance has expanded on two main lines: i) to select strains of species, currently in use commercially, which have increased tolerance to environmental extremes; and ii) to utilize molecular information, including expressed sequence tags and genome sequence data, to determine the underlying genetic factors that control longevity and stress tolerance of EPN. However, given the inherent limitations of EPN survival ability, it is likely that improved formulation will be the major factor to enhance EPN longevity and, perhaps, increase the range of applications. © The Society of Nematologists 2012.

Peters A.,E nema GmbH
Applied Microbiology and Biotechnology | Year: 2013

While nematodes are most commonly known for their negative impact on plants, animals, and humans, there are a number of species which are commercially explored. This review highlights some of the most important success stories for the application of nematodes. They are used as bioindicators in ecological and toxicity studies, as model organisms for elucidating fundamental biological questions and for high throughput screening of drugs. Besides these indirect uses, direct applications include the use of Beddingia siricidicola against a major forest pest and the commercialization of Steinernema, Heterorhabditis, and Phasmarhabditis as biological pest control products. New directions for the commercialization of nematodes are the use as living food, specifically loaded with essential nutrients for various fish and shrimp larvae. Even human parasites or closely related species have been successfully used for curing autoimmune disorders and are currently in the process of being developed as drugs. With the striving development of life sciences, we are likely to see more applications for nematodes in the future. A prerequisite is that we continue to explore the vast number of yet undiscovered nematode species. © 2013 Springer-Verlag Berlin Heidelberg.

Honnens H.,University of Kiel | Assheuer T.,University of Kiel | Ehlers R.-U.,University of Kiel | Ehlers R.-U.,e nema GmbH
Aquaculture International | Year: 2014

The nematode Panagrolaimus sp. (strain NFS-24-5) may have potential as a live food organism for larvae of several marine species. It can be mass-produced in liquid culture and is desiccation tolerant enabling long-term storage and transportation. Nematodes lack the essential fatty acid docosahexaenoic acid (DHA), so this investigation examined an enrichment procedure by incubating nematodes in S.presso® (INVE Aquaculture, Belgium), a commercial enrichment product. Mass-produced nematodes from liquid cultures on yeast cells were cleaned and then exposed to concentrations of 0.1-3 % S.presso® for 24 h at 200,000 nematodes ml-1. Nematode viability was >90 % after the treatment. Following enrichment percentage, total lipid ranged from 23.6 to 33.3 % of nematode dry matter, and nematodes incubated in 3 % S.presso® had a significantly higher lipid percentage than untreated controls. Enrichment was successful in increasing the percentage of DHA, and a maximum value of 5.8 % of total fatty acids was achieved. The results of enrichment of Panagrolaimus sp. (strain NFS-24-5) following treatment with 3 % S.presso® should promote the carrying out of feeding trials to test the efficacy of the nematodes as a live food for larval marine fish and crustaceans. © 2013 Springer Science+Business Media Dordrecht.

Ehlers R.-U.,University of Kiel | Strauch O.,E nema GmbH | Seychelles L.,University of Kiel | Ayub F.,E nema GmbH
Nematology | Year: 2013

Life cycle analysis data of the free-living, bacterial-feeding Panagrolaimus sp. strain NFS 24-5 were assessed at different temperatures using a hanging drop method with single male and female individuals and a food density of 3 × 109 Escherichia coli cells ml?1. Lifespan at the moment when the first egg was laid was 5.7 days at 21°C and 4 days at 25, 27 and 29°C. The intrinsic rate of natural increase (rm) was 0.53 at 21°C, 0.81 at 25°C, 0.93 at 27°C and 0.81 at 29°C, corresponding to population doubling times (PDT = ln 2/rm) of 1.3, 0.9, 0.7 and 0.9 days, respectively. Over 200 offspring per female were produced at 27°C. All other temperatures yielded fewer offspring. When females were kept without males, the life span was 49 days, whereas the last reproductive female (hanging drop with male individual) died after 16.5 days. These data will contribute to the interpretation of nematode population dynamics recorded in liquid culture. © Koninklijke Brill NV, Leiden, 2013.

Honnens H.,University of Kiel | Assheuer T.,University of Kiel | Ehlers R.-U.,University of Kiel | Ehlers R.-U.,E nema GmbH
Nematology | Year: 2013

Panagrolaimus sp. strain NFS-24-5 has potential to be used as live food for early stages of fish and crustacean species in marine aquaculture. One constraint to its commercialisation is the lack of a method that enables storage of nematodes over a longer time span. The objective of this study was to develop a procedure to transfer nematodes into a dormant state by desiccation. The nematodes were concentrated at densities of 25, 50, 100 and 200 × 103 individials cm-2 on nylon net or cellulose paper, preconditioned for 72 h at 97.3% relative humidity (RH) and then stored at 52.9 or 32.8% RH for 1 week. Cellulose was a better carrier for the nematodes. Survival of the nematodes was reduced only at the highest nematode density on both materials. The water activity of desiccated nematodes was 0.44 and 0.33 at 52.9% and 32.8% RH, respectively, well beyond a point to prevent microbial growth. After storage over a period of 10 weeks at 25 × 103 nematodes cm-2 at 52.9 and 32.8% RH, 92% of the nematodes were still alive. Monitoring the size distribution revealed no changes at 52.9% RH, but there were more of the larger nematodes dying at 32.8% RH in two out of three experiments. The method can be used to store quiescent Panagrolaimus sp. (strain NFS-24-5) for transportation and use in small scale feeding experiments for marine fish and crustacean larvae. © 2013 Koninklijke Brill NV, Leiden.

Honnens H.,University of Kiel | Ehlers R.-U.,E nema GmbH
Nematology | Year: 2013

Free-living nematodes have potential to be used as live food for early life stages of several species in marine aquaculture. Panagrolaimus sp. displays several favourable characteristics for this application. The present study proved the feasibility of propagation in monoxenic liquid culture on Saccharomyces cerevisiae. The development of yeast cell density, nematode numbers and size distribution was assessed daily for 15 days. After a lag phase of 4 days the inoculated first-stage juveniles started development to adults. Yields in terms of nematode number as well as biomass were highly variable. The maximum number of nematodes varied from 45 000 to 238 000 ml-1 and maximum biomass from 49 to 143 g l-1. Information on size, dry and wet weight of the nematodes is provided. The size spectrum of Panagrolaimus sp. individuals ranged from 176 × 8 μm to 1377 × 61 μm and 8.15 to 3202.39 ng wet weight. Water content of the nematodes was 71.7 ± 2.5%, so dry weight per individual was 2.31-905.95 ng. Differentiation of juvenile stages by body length was not possible. Based on comparison of dry weight per individual the Panagrolaimus sp. might be used as a substitute for rotifers, a commonly used live food organism. © 2013 Koninklijke Brill NV, Leiden.

PubMed | Guangdong Entomological Institute and E nema GmbH
Type: Journal Article | Journal: FEMS microbiology letters | Year: 2016

Photorhabdus (Enterobacteriaceae) bacteria are pathogenic to insects and mutualistic with entomopathogenic Heterorhabditis nematodes. Photorhabdus luminescens subsp. akhurstii LN2, associated with Heterorhabditis indica LN2, shows nematicidal activity against H. bacteriophora H06 infective juveniles (IJs). In the present study, an rpoS mutant of P. luminescens LN2 was generated through allelic exchange to examine the effects of rpoS deletion on the nematicidal activity and nematode development. The results showed that P. luminescens LN2 required rpoS for nematicidal activity against H06 nematodes, normal IJ recovery and development of H. indica LN2, however, not for the bacterial colonization in LN2 and H06 IJs. This provides cues for further understanding the role of rpoS in the mutualistic association between entomopathogenic nematodes and their symbionts.

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