| desiccation survival of populations of the entomopathogenic nematodes steinernema feltiae and heterorhabditis megidis from greece and the uk. | the desiccation survival and ability to control water loss during drying of individual infective juveniles (ijs) of populations of steinernema feltiae and heterorhabditis megidis from greece and the uk were examined at different relative humidities. survival at all relative humidities was for minutes only and there was no evidence of enhanced survival of the populations of either species from greece compared with those from the uk. the survival of individuals of both populations of h. megidis wa ... | 1997 | 9166440 |
| the efficacy of entomopathogenic nematodes for controlling housefly infestations of intensive pig units. | the efficacy of the entomopathogenic nematodes steinernema feltiae and heterorhabditis megidis after formulation into a housefly bait was compared with a commercial bait formulation of methomyl for the control of houseflies in a u.k. pig farm. the housefly infestation was confined to the farrowing unit, which consisted of ten farrowing houses, where two adjacent houses were sequentially re-stocked with pregnant sows at weekly intervals. shortly after re-stocking, one house was baited with one of ... | 1998 | 9513938 |
| successful parasitation of locusts by entomopathogenic nematodes is correlated with inhibition of insect phagocytes. | the entomopathogenic nematodes heterorhabditis megidis and steinernema feltiae turned out to be successful antagonists of the orthopteran insects locusta migratoria and schistocerca gregaria. the death rate of locusts maintained on nematode-inoculated sand was remarkably high. even dosages as low as one nematode per cubic centimeter of sand killed approximately 50% of the locusts within 10 days. the impact of parasitation on locusts' immune defense was closely investigated for l. migratoria para ... | 1999 | 10066395 |
| antibiotic production in relation to bacterial growth and nematode development in photorhabdus--heterorhabditis infected galleria mellonella larvae. | the population of photorhabdus luminescens c9, bacterial symbiont of the entomopathogenic nematode, heterorhabditis megidis 90, increased rapidly to 1.2-2.6x10(9) cells g(-1) wet galleria mellonella larvae within 24 h of nematode infection of the larvae, and maintained a relatively constant level (1.2-2.0x10(10) cells g(-1)) through the entire 14-day period of nematode development. the antibiotic, 3, 5-dihydroxy-4-isopropylstilbene, was produced by p. luminescens c9 after 24 h of nematode infect ... | 2000 | 10930742 |
| influence of the aeration rate on the yields of the biocontrol nematode heterorhabditis megidis in monoxenic liquid cultures. | the entomopathogenic nematode-bacterium complex heterorhabditis megidis photorhabdus luminescens was cultured in 10-1 internal loop bioreactors with marine impellers at aeration rates of 0.3 vvm and 0.7 vvm. process parameters like impeller velocity and oxygen saturation were controlled at equal set points. the bacterial density was assessed at 24 h. nematode dauer juveniles (dj) were then inoculated and the development to adults after 8 days and final dj yields after 16 days were recorded. the ... | 2000 | 10951998 |
| virulence of entomopathogenic nematodes to pecan weevil larvae, curculio caryae (coleoptera: curculionidae), in the laboratory. | the pecan weevil, curculio caryae (horn), is a key pest of pecans in the southeast. entomopathogenic nematodes have been shown to be pathogenic toward the larval stage of this pest. before this research, only three species of nematodes had been tested against pecan weevil larvae. in this study, the virulence of the following nine species and 15 strains of nematodes toward fourth-instar pecan weevil was tested: heterorhabditis bacteriophora poinar (baine, hp88, oswego, nj1, and tf strains), h. in ... | 2001 | 11233136 |
| characterization of endospore-forming bacteria associated with entomopathogenic nematodes, heterorhabditis spp., and description of paenibacillus nematophilus sp. nov. | endospore-forming bacteria were isolated from insect-pathogenic nematodes, heterorhabditis spp., from three diverse geographical locations. spindle-shaped sporangia of these bacteria adhere to the free-living infective stage of the nematode, which carries them to new insect hosts, where the bacterium reproduces. these isolates were characterized based on phenotypic and chemotaxonomic properties and 16s rrna gene sequences. analysis of the 16s rrna gene placed the isolates within the genus paenib ... | 2003 | 12710609 |
| effects of paenibacillus nematophilus on the entomopathogenic nematode heterorhabditis megidis. | the insect parasitic nematodes heterorhabditis spp. are mutualistically associated with entomopathogenic bacteria, photorhabdus spp. a novel association has been detected between h. megidis isolate eu17 and the endospore-forming bacterium paenibacillus nematophilus. p. nematophilus sporangia adhere to infective juveniles (ijs) of h. megidis and develop in insect hosts along with the nematodes and their symbiont. we tested the effects of p. nematophilus on h. megidis. the yield and quality (size, ... | 2004 | 15707868 |
| whole-genome comparison between photorhabdus strains to identify genomic regions involved in the specificity of nematode interaction. | the bacterium photorhabdus establishes a highly specific association with heterorhabditis, its nematode host. photorhabdus strains associated with heterorhabditis bacteriophora or heterorhabditis megidis were compared using a photorhabdus dna microarray. we describe 31 regions belonging to the photorhabdus flexible gene pool. distribution analysis of regions among the photorhabdus genus identified loci possibly involved in nematode specificity. | 2006 | 16385072 |
| a novel antimicrobial epoxide isolated from larval galleria mellonella infected by the nematode symbiont, photorhabdus luminescens (enterobacteriaceae). | a novel antimicrobial epoxide, 2-isopropyl-5-(3-phenyl-oxiranyl)-benzene-1,3-diol (1), was identified from larval galleria mellonella infected by a symbiotically associated bacterium-nematode complex (photorhabdus luminescens c9-heterorhabditis megidis 90). its structure was determined with spectroscopic analysis and confirmed by chemical synthesis starting from a known antibiotic, 2-isopropyl-5-(2-phenylethenyl)-benzene-1,3-diol (2). epoxide 1 was active against bacillus subtilis, escherichia c ... | 2006 | 16644226 |
| photorhabdus temperata subsp. cinerea subsp. nov., isolated from heterorhabditis nematodes. | during the characterization of symbiotic bacteria of hungarian entomopathogenic nematode isolates, a number of bacteria (including strain 3107(t)) isolated from heterorhabditis downesi and heterorhabditis megidis showed only moderate 16s rrna gene sequence similarity to the type strains of all described photorhabdus species and subspecies. on the basis of the 16s rrna gene sequence, the phylogenetic relationships of these isolates were uncertain, because of the low bootstrap values. using gyrb s ... | 2008 | 18984696 |
| entomopathogenic nematodes for control of insect pests above and below ground with comments on commercial production. | entomopathogenic nematodes (epns) have been utilized in classical, conservation, and augmentative biological control programs. the vast majority of applied research has focused on their potential as inundatively applied augmentative biological control agents. extensive research over the past three decades has demonstrated both their successes and failures for control of insect pests of crops, ornamental plants, trees and lawn and turf. in this paper we present highlights of their development for ... | 2012 | 23482993 |
| two symbiotic bacteria of the entomopathogenic nematode heterorhabditis spp. against galleria mellonella. | the entomopathogenic nematode heterorhabditis spp. is considered a promising agent in the biocontrol of injurious insects of agriculture. however, different symbiotic bacteria associated with the nematode usually have different specificity and virulence toward their own host. in this study, two symbiotic bacteria, ly2w and nk, were isolated from the intestinal canals of two entomopathogenic nematode heterorhabditis megidis 90 (pdsj1 and pdsj2) from galleria mellonela, separately. to determine th ... | 2017 | 27889603 |
| influence of soil on the efficacy of entomopathogenic nematodes in reducing diabrotica virgifera virgifera in maize. | the use of entomopathogenic nematodes is one potential non-chemical approach to control the larvae of the invasive western corn rootworm (diabrotica virgifera virgifera leconte, coleoptera: chrysomelidae) in europe. this study investigated the efficacy of heterorhabditis bacteriophora poinar (rhabditida: heterorhabditidae), heterorhabditis megidis poinar, jackson and klein (rh., heterorhabditidae) and steinernema feltiae filipjev (rh., steinernematidae) in reducing d. v. virgifera as a function ... | 2010 | 21124754 |
| virulence of entomopathogenic nematodes to the western masked chafer cyclocephala hirta (coleoptera: scarabaeidae). | predictability is a key challenge in biological control of white grubs with entomopathogenic nematodes. most field test failures have been attributed to the use of inappropriate nematode strains. we evaluated several species and strains of entomopathogenic nematodes (heterorhabditidae and steinernematidae) against chafer cyclocephala hirta in a soil and pot bioassay at 25 degrees c. the nj65 strain of steinernema glaseri, isolated from new jersey, outperformed all other steinernematid and hetero ... | 1998 | 9589628 |
| phased activity in heterorhabditis megidis infective juveniles. | the infectivity of heterorhabditis megidis infective juveniles (ijs) increases during storage in water. we investigated whether this change can be related to other features of the ijs' behaviour. ijs were stored in water for 4 weeks at 20 degrees c, and the following parameters were assessed at intervals: infectivity for galleria mellonella, dispersal in sand, host-finding on agar, and the percentage of ijs active in water. in addition, the behaviour of the ijs in water was described using 7 cat ... | 2002 | 12118716 |
| the effect of initial dose on the recovery and final yields of heterorhabditis megidis (rhabditida: heterorhabditidae) in larvae of the great wax moth, galleria mellonella. | the aim of this study was to determine the effect of different initial doses of the infective juveniles (ijs) (50 ijs, 200 ijs, 1000 ijs) of heterorhabditis megidis poinar (rhabditida: heterorhabditidae) strain ism15/09 on recovery, final yields and percent final yields in larvae galleria mellonella ( l.). percent recovery was not directly related to initial dose. final yields also did not change with the initial dose. however, percent yields was highly negatively correlated with initial dose of ... | 2014 | 24827089 |
| molecular detection of predation by soil micro-arthropods on nematodes. | the relative importance of the factors driving change in the population dynamics of nematodes in the soil is almost completely unknown. top-down control by micro-arthropod predators may have a significant impact on nematode population dynamics. we report experiments showing that mites and collembola were capable of reducing nematode numbers in the laboratory and were feeding on a targeted nematode species in the field. a pcr-based approach was developed for the detection of predation on three sp ... | 2006 | 16689911 |
| simultaneous feeding by aboveground and belowground herbivores attenuates plant-mediated attraction of their respective natural enemies. | herbivore-damaged plants emit volatile organic compounds that attract natural enemies of the herbivores. this form of indirect plant defence occurs aboveground as well as belowground, but it remains unclear how simultaneous feeding by different herbivores attacking leaves and roots may affect the production of the respective defence signals. we employed a setup that combines trapping of volatile organic signals and simultaneous measurements of the attractiveness of these signals to above and bel ... | 2007 | 17845293 |
| belowground chemical signaling in maize: when simplicity rhymes with efficiency. | maize roots respond to feeding by larvae of the beetle diabrotica virgifera virgifera by releasing (e)-beta-caryophyllene. this sesquiterpene, which is not found in healthy maize roots, attracts the entomopathogenic nematode heterorhabditis megidis. in sharp contrast to the emission of virtually only this single compound by damaged roots, maize leaves emit a blend of numerous volatile organic compounds in response to herbivory. to try to explain this difference between roots and leaves, we studi ... | 2008 | 18443880 |
| systemic root signalling in a belowground, volatile-mediated tritrophic interaction. | plants attacked by leaf herbivores release volatile organic compounds (vocs) both locally from the wounded site and systemically from non-attacked tissues. these volatiles serve as attractants for predators and parasitoids. this phenomenon is well described for plant leaves, but systemic induction of vocs in the roots has remained unstudied. we assessed the spatial and temporal activation of the synthesis and release of (e)-β-caryophyllene (eβc) in maize roots upon feeding by larvae of diabrotic ... | 2011 | 21477121 |
| effect of soil moisture and a surfactant on entomopathogenic nematode suppression of the pecan weevil, curculio caryae. | our overall goal was to investigate several aspects of pecan weevil, curculio caryae, suppression with entomopathogenic nematodes. specifically, our objectives were to: 1) determine optimum moisture levels for larval suppression, 2) determine suppression of adult c. caryae under field conditions, and 3) measure the effects of a surfactant on nematode efficacy. in the laboratory, virulence of heterorhabditis megidis (uk211) and steinernema carpocapsae (all) were tested in a loamy sand at gravimet ... | 2006 | 19259466 |
| entomopathogenic nematodes for the management of agrotis ipsilon: effect of instar, nematode species and nematode production method. | previous laboratory studies have indicated the potential of some entomopathogenic nematode (epn) species for the control of larvae of the black cutworm (bcw). to determine the most promising epn species and the most susceptible bcw stages, a more in-depth evaluation of seven epn species against different bcw instars was carried out, the efficacies of in vitro- and in vivo-produced epns were compared and the suitability of bcw instars for epn reproduction was examined. | 2012 | 22344709 |
| draft genome sequence of photorhabdus temperata strain meg1, an entomopathogenic bacterium isolated from heterorhabditis megidis nematodes. | photorhabdus temperata strain meg1 is an entomopathogenic bacterium that forms a symbiotic association with heterorhabditis nematodes. we report here a 4.9-mbp draft genome sequence for p. temperata strain meg1, with a g+c content of 43.18% and containing 4,340 candidate protein-coding genes. | 2014 | 25502670 |
| temperature effects on heterorhabditis megidis and steinernema carpocapsae infectivity to galleria mellonella. | the effect of temperature on the infection of larvae of the greater wax moth, galleria mellonella, by heterorhabditis megidis h90 and steinernema carpocapsae strain all, was determined. for both species, infection, reproduction, and development were fastest at 20 to 24 degrees c. infection by both h. megidis and s. carpocapsae occurred between 8 and 16 degrees c; however, neither species reproduced at 8 degrees c. among the nematodes used in experiments at 8 degrees c, no h. megidis and very few ... | 1999 | 19270900 |
| characterization in biological traits of entomopathogenic nematodes isolated from north china. | in a series of bioassays, thirty-one isolates that were collected from diverse locations in northern china and the laboratory kept isolate steinernema carpocapsae all, were compared in order to select superior isolates for biological control of bradysia odoriphaga. virulence of the isolates against b. odoriphaga was significantly different among nematode isolates. tolerance of infective juveniles (ijs) to heat, cold, and desiccation differed significantly among and within species. strains from s ... | 2013 | 24035764 |
| persistence of heterorhabditis infective juveniles in soil: comparison of extraction and infectivity measurements. | the persistence of heterorhabditis megidis in soil was studied over a 4-week period. on days 0, 2, 14, and 28, infective juveniles (ij) were extracted by centrifugal flotation, baermann funnel, and baiting of soil with tenebrio molitor larvae, which were then dissected. extraction efficiencies on day 0 were 82% by centrifugal flotation, 56% by baermann funnel, and 19.8% by bait insect. the relative efficiency of the three methods changed over time. the relationship between the density of nematod ... | 1999 | 19270923 |
| persistence of four heterorhabditis spp. isolates in soil: role of lipid reserves. | infective juveniles of four heterorhabditis isolates (h. bacteriophora hi, h. megidis uk211 and hf85, and h. downesi m245) were stored in moist (pf 1.7) and dry (pf 3.3) loam soil at 20 degrees c for up to 141 days. survival, assessed by the number of nematodes extracted by centrifugal flotation, declined over time, reaching fewer than 18% alive by day 141 for all but one treatment (h. bacteriophora hi in dry soil). the infectivity of nematodes in soil for tenebrio molitor also declined over tim ... | 2002 | 19265925 |
| evaluation of a contraction flow field on hydrodynamic damage to entomopathogenic nematodes-a biological pest control agent. | mechanized production and delivery of biological pesticides presents challenges because the biological agents must remain viable during these processes. this study evaluates the effect of flow through an abrupt contraction, where flow characteristics similar to that found within bioprocesses and spray equipment are developed, on damage to a benchmark biological pest control agent, entomopathogenic nematodes (epns). an opposed-pistons, contraction flow device generated volumetric flow rates rangi ... | 2004 | 15007846 |
| directional movement of entomopathogenic nematodes in response to electrical field: effects of species, magnitude of voltage, and infective juvenile age. | entomopathogenic nematodes respond to a variety of stimuli when foraging. previously, we reported a directional response to electrical fields for two entomopathogenic nematode species; specifically, when electrical fields were generated on agar plates steinernema glaseri (a nematode that utilizes a cruiser-type foraging strategy) moved to a higher electric potential, whereas steinernema carpocapsae, an ambush-type forager, moved to a lower potential. thus, we hypothesized that entomopathogenic n ... | 2012 | 21945052 |
| strains of photorhabdus spp. associated with polish heterorhabditis isolates: their molecular and phenotypic characterization and symbiont exchange. | the relationships between six bacterial symbionts of the entomopathogenic nematodes heterorhabditis bacteriophora and heterorhabditis megidis from poland to species and subspecies of the genus photorhabdus were evaluated. this study was based on phylogenetic analysis of sequence data of five genes: 16s rrna, gyrb, reca, gltx, and dnan. the bacteria were also characterized phenotypically by biochemical and physiological tests. our results have revealed that the photorhabdus strains isolated from ... | 2017 | 28382473 |
| oral toxicity of photorhabdus culture media on gene expression of the adult sweetpotato whitefly, bemisia tabaci. | the oral toxicity of culture media of the symbiotic bacteria, photorhabdus temperata, mutually associated with entomopathogenic nematode heterorhabditis megidis and photorhabdus luminescens ssp. laumondii (tt01) mutually associated with heterorhabditis bacteriophora, were investigated in the adults of bemisia tabaci. the oral ingestion of sucrose diet solutions (20%) containing bacteria-free supernatant of the culture media from symbiotic bacteria gradually increased mortalities and was complete ... | 2012 | 22041203 |
| survey of heterorhabditidae and steinernematidae (rhabditida, nematoda) in western canada. | a survey was done in the summer months along the alaska highway, in other parts of british columbia, in northern alberta, and in the yukon territory for steinernematid and heterorhabditid nematodes occurring in the top 10 cm of soil. steinernema feltiae and steinernema spp. were found at 18 and heterorhabditis megidis at 7 sites of 125 sampled. most nematodes were found where visible insect infestation occurred and where human influence on the habitat was substantial (e.g., agricultural, foreste ... | 1993 | 19279830 |
| establishment, persistence, and introgression of entomopathogenic nematodes in a forest ecosystem. | entomopathogenic nematodes (epn) are currently marketed worldwide for use in inundative biological control, where the applied natural enemy population (rather than its offspring) is expected to reduce insect numbers. unlike classical biological control, in inundative control natural enemy establishment is not crucial in order to achieve pest suppression. field trials in irish forestry provided the opportunity to test predictions regarding the establishment of two exotic (steinernema carpocapsae ... | 2008 | 18488631 |
| effect of photorhabdus luminescens phase variants on the in vivo and in vitro development and reproduction of the entomopathogenic nematodes heterorhabditis bacteriophora and steinernema carpocapsae. | photorhabdus luminescens (enterobacteriaceae) is a symbiont of entomopathogenic nematodes heterorhabditis spp. (nematoda: rhabditida) used for biological control of insect pests. for industrial mass production, the nematodes are produced in liquid media, pre-incubated with their bacterial symbiont, which provides nutrients essential for the nematode's development and reproduction. particularly under in vitro conditions, p. luminescens produces phase variants, which do not allow normal nematode d ... | 2001 | 11311434 |
| polyphasic classification of the genus photorhabdus and proposal of new taxa: p. luminescens subsp. luminescens subsp. nov., p. luminescens subsp. akhurstii subsp. nov., p. luminescens subsp. laumondii subsp. nov., p. temperata sp. nov., p. temperata subsp. temperata subsp. nov. and p. asymbiotica sp. nov. | the taxonomic position of photorhabdus strains was examined through the results of dna relatedness (s1 nuclease method) studies associated with the determination of delta tm, 16s rrna phylogenetic inferences and phenotypic characterization, including morphological, auxanographic, biochemical and physiological properties. three genomic species were delineated on a consensus assessment. one of these species corresponded to photorhabdus luminescens, since strains were at least 50% related to the ty ... | 1999 | 10555346 |
| entomopathogenic nematodes as control agents of developmental stages of the black-legged tick, ixodes scapularis. | thirteen species or strains of entomopathogenic nematodes of the genera steinernema and heterorhabditis were tested in vitro against unfed and engorged larvae, nymphs, and adults of the black-legged tick, ixodes scapularis. nematodes were pathogenic to engorged female ticks, but not to unfed or engorged larvae, nymphs, males, and unfed females. steinernema riobravis (355) and heterorhabditis megidis (m145) killed ticks most rapidly, with mean day of death postinfection of 2.5 and 3.5 days, respe ... | 1998 | 9920301 |