Biological traits of native Indian entomopathogenic nematodes against gram pod borer Helicoverpa armigera (Hubner) infecting chickpea

Aim: The present study was aimed at providing suitable EPN-based eco-friendly management strategy for H. armigera infesting chickpea, which is an alternate option to pesticides. Methodology: Efficacy of ten native EPNs was tested against gram pod borer H. armigera in vitro by measuring their penetration abilities and multiplication capabilities. The efficacy of three promising EPNs against 2nd, 3rd and 4th instars H. armigera larvae and pupal stages were also tested in earthen pots. Results: Among the EPNs, Steinernema sp. (EPN 05 and 09) and Heterorhabditis sp. (EPN 06) were the most promising against H. armigera, causing 100 percent mortality within 72 hrs. Heterorhabditis sp. (EPN 06) showed the maximum penetration, followed by Steinernema sp. (EPN 05 and 09) whereas the Oscheius sp. (EPN 04) having the minimum penetration ability. Steinernema sp. (EPN 05) multiplied the most followed by Oscheius sp. (EPN 07), while Heterorhabditis sp. (EPN 06) multiplied the least. The 2nd instar larvae of H. armigera were most susceptible to EPNs, followed by the 3rd and 4th instar larvae. The results showed that the Heterorhabditis sp. (EPN 06), followed by Steinernema sp. (EPN 05 and 09) were highly pathogenic against H. armigera pre-pupa and pupa. Interpretation: As observed the 5th instar of H. armigera larvae was more suited for multiplication demonstrates that this insect is suitable for producing EPNs. Therefore, more field experiments are required to demonstrate the efficacy of these promising EPNs in managing H. armigera sustainably. Key words: Biopesticides, Cicer arietinum, Heterorhabditis, Insects, Oscheius, Steinernema