PHYSICAL STRESSORS AFFECTING INTERACTIONS OF SPODOPTERA EXIGUA (HÜBNER) (LEPIDOPTERA: NOCTUIDAE) AND AN ENTOMOPATHOGENIC NEMATODE

1994 ◽  
Vol 126 (2) ◽  
pp. 261-267 ◽  
Author(s):  
Graham S. Thurston ◽  
Harry K. Kaya
Keyword(s):  
Temperature Control ◽  
Room Temperature ◽  
Spodoptera Exigua ◽  
Cold Shock ◽  
Entomopathogenic Nematode ◽  
Physiological State ◽  
Symbiotic Bacterium ◽  
Shock Treatment ◽  
Steinernema Carpocapsae ◽  
Lepidoptera Noctuidae

AbstractCuticular damage of Spodoptera exigua (Hübner) pupae, caused by puncturing with a sterilized insect pin, resulted in enhanced susceptibility to the entomopathogenic nematode Steinernema carpocapsae (Weiser), but cold shock (5 °C for 24 h) did not alter susceptibility. The additional avenue of entry for the nematode probably accounted for the increased mortality of the damaged pupae. In all treatments, some dead pupae contained Xenorhabdus nematophilus (Poinar and Thomas), the symbiotic bacterium of S. carpocapsae, but no nematodes. More nematode-killed pupae containing X. nematophilus but no nematodes were found in the cold-shock treatment than in the room-temperature control (62.6 versus 46.9%). In contrast, fewer nematode-killed pupae containing X. nematophilus but no nematodes were found in the damaged pupae compared with the undamaged control (25.0 versus 45.1%). Moreover, mortality of nematodes within the cadavers of cold-shocked insects was higher than in the cadavers of non-cold-shocked insects. These results suggest that the stressors, cold shock and cuticular damage, produce fundamentally different responses in insects exposed to them, and that the physiological state of the insect greatly influences nematode survival in the host and hence nematode recycling in the environment.

scholarly journals Canadian entomopathogenic nematode isolates: virulence against black cutworm (Lepidoptera: Noctuidae)

2013 ◽  
Vol 93 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Guy Bélair ◽  
Louis Simard ◽  
Julie Dionne
Keyword(s):  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Steinernema Carpocapsae ◽  
Agrotis Ipsilon ◽  
Black Cutworm ◽  
Laboratory Conditions ◽  
Lepidoptera Noctuidae

The virulence of ten indigenous and two commercial isolates of entomopathogenic nematodes against the black cutworm, Agrotis ipsilon, was assessed under laboratory conditions. When comparing commercial isolates, Steinernema carpocapsae exhibited higher virulence than S. feltiae. One indigenous isolate of S. carpocapsae (6Sc) provided similar or higher virulence than the commercial isolate against black cutworm larvae. An indigenous strain of S. kraussei demonstrated low virulence in our study.

scholarly journals Spodoptera frugiperda transcriptional response to infestation by Steinernema carpocapsae

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Louise Huot ◽  
Simon George ◽  
Pierre-Alain Girard ◽  
Dany Severac ◽  
Nicolas Nègre ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Fat Body ◽  
Entomopathogenic Nematode ◽  
Transcriptional Response ◽  
Early Time ◽  
Symbiotic Bacterium ◽  
Steinernema Carpocapsae ◽  
Differentially Expressed ◽  
Xenorhabdus Nematophila ◽  
Transcriptional Responses

Abstract Steinernema carpocapsae is an entomopathogenic nematode (EPN) used in biological control of agricultural pest insects. It enters the hemocoel of its host via the intestinal tract and releases its symbiotic bacterium Xenorhabdus nematophila. In order to improve our knowledge about the physiological responses of its different hosts, we examined the transcriptional responses to EPN infestation of the fat body, the hemocytes and the midgut in the lepidopteran pest Spodoptera frugiperda. The tissues poorly respond to the infestation at an early time post-infestation of 8 h with only 5 genes differentially expressed in the fat body of the caterpillars. Strong transcriptional responses are observed at a later time point of 15 h post-infestation in all three tissues. Few genes are differentially expressed in the midgut but tissue-specific panels of induced metalloprotease inhibitors, immune receptors and antimicrobial peptides together with several uncharacterized genes are up-regulated in the fat body and the hemocytes. Among the most up-regulated genes, we identified new potential immune effectors, unique to Lepidoptera, which show homology with bacterial genes of unknown function. Altogether, these results pave the way for further functional studies of the responsive genes’ involvement in the interaction with the EPN.

Mechanisms of specificity of association between the nematode Steinernema scapterisci and its symbiotic bacterium

Parasitology ◽  
1997 ◽  
Vol 114 (5) ◽  
pp. 483-488 ◽  
Author(s):  
P. S. GREWAL ◽  
M. MATSUURA ◽  
V. CONVERSE
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Symbiotic Bacterium ◽  
Bacterial Symbiont ◽  
Steinernema Carpocapsae ◽  
Infective Juvenile ◽  
Symbiotic Bacteria ◽  
Bacterial Symbionts ◽  
First Report ◽  
Successful Isolation

We suggest a new mechanism for the maintenance of specificity of the association between the entomopathogenic nematode Steinernema scapterisci and its symbiotic bacteria. We evaluated the development and reproduction of infective and non-infective juvenile S. scapterisci in monoxenic combinations with its symbiotic bacteria, Xenorhabdus sp. ‘S’ and with the bacterial symbiont of Steinernema carpocapsae and Steinernema riobravis. Although development of non-infective stages occurred on all Xenorhabdus spp., the development of infective juveniles to the 4th stage (‘dauer’ recovery) was significantly delayed and reduced with X. nematophilus and Xenorhabdus sp. ‘R’, the bacterial symbionts of S. carpocapsae and S. riobravis, respectively. ‘Dauer’ recovery improved significantly when the cultures of X. nematophilus and Xenorhabdus sp. ‘R’ were supplemented with cell-free filtrates from Xenorhabdus sp. ‘S’. The infective juvenile S. scapterisci produced in all 3 cultures were virulent to Galleria mellonella larvae, confirming successful retention of Xenorhabdus from other steinernematids in their intestine. In fact, S. scapterisci infective juveniles containing X. nematophilus or Xenorhabdus sp. ‘R’ were more virulent to G. mellonella than those containing their natural symbiont, Xenorhabdus sp. ‘S’. We believe that this is the first demonstration of the symbiont-specific exit of infective juveniles from the ‘dauer’ phase which represents the finest level of specificity of bacteria–nematode association. This is also the first report of successful isolation of the natural symbiont of S. scapterisci.

scholarly journals First report of the entomopathogenic nematode, Steinernema carpocapsae, from Moghan region of Iran and its efficacy against the turnip moth, Agrotis segetum Denis and Schiffermuller (Lepidoptera: Noctuidae), larvae

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Laleh Ebrahimi ◽  
Zahra TanhaMaafi ◽  
Parviz Sharifi
Keyword(s):  
Entomopathogenic Nematode ◽  
Lethal Effect ◽  
Molecular Data ◽  
Steinernema Carpocapsae ◽  
Steinernema Feltiae ◽  
Agrotis Segetum ◽  
Likelihood Method ◽  
Bootstrap Analysis ◽  
Turnip Moth ◽  
Lepidoptera Noctuidae

Abstract During a survey of entomopathogenic nematodes (EPNs) in Moghan region of Iran in 2015, a steinernematid species was isolated, using the Galleria-baiting method. Based on its morphological and phylogenetic analysis of molecular data, the isolate was identified as Steinernema carpocapsae. The ITS rDNA sequence was deposited in NCBI (National Center for Biotechnology Information) with accession number of MF187616.1. Nucleotide row data was edited, using MEGA 6.0 software, and homologous sequences were involved in analysis, using Blast software. Sequences were aligned using Clustal W. Bootstrap analysis. The phylogenetic tree was constructed by the maximum likelihood method, using MEGA 6.0 software, and Steinernema feltiae was used as out-group. The turnip moth, Agrotis segetum Denis and Schiffermuller (Lepidoptera: Noctuidae), is one of the most important and destructive cutworm pests in Moghan. Therefore, the lethal effect of S. carpocapsae isolate Moghan (IRMoghan) was evaluated in a soil assay against the last instar larvae of A. segetum under laboratory conditions. The bioassay results showed high susceptibility of the larvae to S. carpocapsae. The LC10, LC50, and LC90 values were 9.9, 54.13, and 246.2 IJs (infective juveniles) per larva of the pest, respectively (χ2 = 7.36; df = 3, P value = 0.061). Reproduction of the EPNs within the dissected cadavers was observed. The bioassay results indicated that the new isolate is a promising biocontrol agent against A. segetum larvae with success recycling through them.

Host recognition behaviour predicts host suitability in the entomopathogenic nematode Steinernema carpocapsae (Rhabditida: Steinernematidae)

Parasitology ◽  
1996 ◽  
Vol 113 (6) ◽  
pp. 573-579 ◽  
Author(s):  
E. E. Lewis ◽  
M. Ricci ◽  
R. Gaugler
Keyword(s):  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Behavioural Response ◽  
Host Suitability ◽  
Nematode Infection ◽  
Steinernema Carpocapsae ◽  
Host Recognition ◽  
Recognition Response ◽  
Control Surfaces ◽  
Lepidoptera Noctuidae

SUMMARYSteinernema carpocapsae (Rhabditida: Steinernematidae) host recognition behaviour was assessed and compared with 2 measures of host suitability. Previous research showed that S. carpocapsae infective juveniles respond to host cues in a hierarchical order, with attraction to Galleria mellonella volatiles being stimulated by contact with G. mellonella cuticle. We measured host recognition behaviour by calculating the percentage response of S. carpocapsae infective juveniles to volatiles produced by G. mellonella last instars after the nematodes were exposed to the cuticle of 11 candidate arthropod hosts and 2 control surfaces. Host suitability was measured by nematode-induced mortality to candidate hosts at 2 nematode doses and the level of reproduction supported by each host. The highest recognition response was scored for Agrotis ipsilon (Lepidoptera: Noctuidae). This insect also incurred nearly 100% mortality due to nematode infection and supported the highest level of reproduction. Non-insect arthropods tested (Chilopoda and Isopoda) stimulated no behavioural response and were not susceptible to nematode infection. Other insect species elicited intermediate levels of the recognition response. There were significant correlations between behavioural response and nematode-induced mortality at the lower dose. The level of reproduction supported by the candidate hosts was also correlated with S. carpocapsae behavioural response.

scholarly journals Studying the Symbiotic Bacterium Xenorhabdus nematophila in Individual, Living Steinernema carpocapsae Nematodes Using Microfluidic Systems

mSphere ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Matthew D. Stilwell ◽  
Mengyi Cao ◽  
Heidi Goodrich-Blair ◽  
Douglas B. Weibel
Keyword(s):  
Entomopathogenic Nematode ◽  
Experimental System ◽  
Symbiotic Bacterium ◽  
Lessons Learned ◽  
Steinernema Carpocapsae ◽  
Infective Juvenile ◽  
Xenorhabdus Nematophila ◽  
Bacterial Populations ◽  
Individual Host ◽  
Host Microbe Interactions

This paper describes an experimental system for directly investigating population dynamics of a symbiotic bacterium,Xenorhabdus nematophila, in its host—the infective stage of the entomopathogenic nematodeSteinernema carpocapsae. Tracking individual and groups of bacteria in individual host nematodes over days and weeks yielded insight into dynamic growth and topology changes of symbiotic bacterial populations within infective juvenile nematodes. Our approach for studying symbioses between bacteria and nematodes provides a system to investigate long-term host-microbe interactions in individual nematodes and extrapolate the lessons learned to other bacterium-animal interactions.

Field Evaluation of Steinernema carpocapsae (Rhabditida: Steinernematidae) Against Black Cutworm (Lepidoptera: Noctuidae) Larvae In Field Corn

1992 ◽  
Vol 27 (4) ◽  
pp. 427-435 ◽  
Author(s):  
Eli Levine ◽  
Hassan Oloumi-Sadeghi
Keyword(s):  
Entomopathogenic Nematodes ◽  
Entomopathogenic Nematode ◽  
Field Evaluation ◽  
Growing Season ◽  
Steinernema Carpocapsae ◽  
Agrotis Ipsilon ◽  
Black Cutworm ◽  
Field Corn ◽  
Lepidoptera Noctuidae ◽  
Better Than

An entomopathogenic nematode, Steinernema carpocapsae (Weiser) All strain (BioVector®), applied at two rates (1.25 and 2.5 × 109 nematodes/ha) was compared with several registered insecticides for controlling black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), larvae during the 1991 growing season in Illinois. Fonofos, tefluthrin and chlorpyrifos were applied at planting time; permethrin and the two rates of nematodes were applied as postemergence rescue treatments. The nematodes generally performed as well as or better than the conventional insecticides in controlling black cutworm larval injury to seedling corn. Bioassays with black cutworm larvae showed that nematode efficacy was lost 8 days after application in the field. Entomopathogenic nematodes hold promise for controlling black cutworms in corn, particularly for corn grown under irrigation.

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