Studies on biological control potential of Steinernema abbasi CS-39 against Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae) by adopting the regression probit model

Shreyansh Srivastava,Ashok Kumar Chaubey,Heena Heena

doi:10.1186/s41938-022-00510-0

Shreyansh Srivastava, Ashok Kumar Chaubey + Show 1 more

Open Access

https://doi.org/10.1186/s41938-022-00510-0

Copy DOI

Abstract

BackgroundIn India, application of entomopathogenic nematodes (EPNs) as a bio-agent against insect pests was known since 5–6 decades with the application of the exotic species Steinernema carpocapsae (DD-136 Strain). EPNs have a strong potential to control the soil-borne insect pests. In the present study isolated strain was identified as Steinernema abbasi and docketed as CS-39. The efficacy of the isolated strain was tested against the American bollworm, Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae).ResultsLaboratory bioassay revealed that the median lethal concentration (LC50 = 83.21 IJs) of the S. abbasi isolate CS-39 was quite sufficient to achieve 100% mortality after 24 h of exposure. Mean mortality percentage was estimated > 75% at all concentrations, i.e., 25, 50, 100 and 200 IJs/larva, and 100% mortality was achieved at 200 IJs/larva after 24 h of concentration exposure. Positive relationship was found at every concentration of exposure and % mortality of the insect pest (H. armigera) after 36 (p < 0.01) and 48 h of exposure (p < 0.02).ConclusionsSteinernema abbasi isolate CS-39 found to be highly virulent to H. armigera. As the result urged, 200 IJs / larva showed 100% mortality at 36 h, whereas 100 IJs / larva showed 100% mortality at 60 h. Difference in time duration might be because of action of bacterial symbionts which were the main precursor of pathogenicity. Extensive study of secondary metabolites of the bacterial symbionts may extend the present study to the new dimension.

Highlights

In India, application of entomopathogenic nematodes (EPNs) as a bio-agent against insect pests was known since 5–6 decades with the application of the exotic species Steinernema carpocapsae (DD-136 Strain)
As far as morphometry is concerned, a little alteration was observed in measurements, while most measurements were in close vicinity
Glazer and Navon (1990) reported the pathogenicity of EPNs against H. armigera larvae under laboratory conditions and found that the complete mortality was first achieved at 200 infective juveniles (IJs)/larva, followed by other concentrations

Summary

Introduction

In India, application of entomopathogenic nematodes (EPNs) as a bio-agent against insect pests was known since 5–6 decades with the application of the exotic species Steinernema carpocapsae (DD-136 Strain). The efficacy of the isolated strain was tested against the American bollworm, Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae). The heliothine species Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is one of the world’s most economic agricultural pest. It can feed and complete its life cycle on more than 180 plant species (Tay et al 2013). EPNs exist in many habitats and have a wide range of tolerance to abiotic and biotic parameters (Grewal et al 1994) Infective stage of these nematodes is third-stage infective juveniles (IJs) that are the only life stage typically found outside the host cadaver, which are non-feeding, resistant to environmental stress and are normally called as dauer larvae. It is the very reason that there has been a tremendous scientific interest in both obtaining EPNs and determining their efficacy against the most damaging species (Canhilal et al 2016 and Kepenekci et al 2018)

Methods

Results

Discussion

Conclusion