Evaluation of Indigenous Entomopathogenic Nematodes as Potential Biocontrol Agents against Wax Moth (Galleria mellonella)

Abstract

The ongoing use of chemical pesticides has been repeatedly associated with the possibility of insecticide resistance and devastating impacts on non-target organisms and human life. Thus, biodiversity is reduced, environmental health is endangered, and pest outbreaks worsen. A comparative efficacy of two locally isolated entomopathogenic nematode (EPN) species viz Heterorhabditis indica (H.I-1a) and Steinernema thermophyllum (S.T-1a) are evaluated against Galleria mellonella fifth instar larvae. Both isolates were obtained from soil samples collected in Tisang village, Khatauli, Meerut (Uttar Pradesh). The larvae were examined every 24 hours for signs of infection. The presence of EPN was confirmed by the mortality and characteristic symptoms in the larvae caused by nematode infection. Infected insect’s cadavers were placed on the filter paper inside the smaller dish (white traps). These white traps were monitored for the appearance of the infective juvenile (IJ) stage of the EPNs. The mortality of larvae was assessed at various concentrations and incubation periods, as indicated by median mortality values determined at different time intervals. EPN concentrations of 0 -100 IJs/larva (in 1 mL distilled water) are tested using a Petri dish bioassay method. Mortality was recorded after 24 and 48 hrs. The strain H.I-1a is found showing a higher mortality rate (9.33 ± 1.10) than S.T-1a (6.67 ± 0.94) after 48 hrs.  The findings suggest that H. indica is better adapted to local environmental conditions and demonstrates a faster infection cycle and greater larval mortality efficiency. Hence, the native isolate H. indica (H.I-1a) holds strong potential as a promising biological control agent for sustainable and ecofriendly pest management strategies in agriculture.