Efficacy of entomopathogenic nematode, Heterorhabditis indica Poinar (Rhabditida: Heterorhabditidae) against the rice yellow stem borer, Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae)

Abstract

In this study, the efficacy of two entomopathogenic nematode species, Heterorhabditis indica and Steinernema asiaticum were evaluated against the larvae of the rice leaf folder, Cnaphalocrosis medinalis and the greater wax moth, Galleria mellonella. Combined inoculation of H. indica and S. asiaticum each at 75 IJs/larva resulted in faster larval mortality on C. medinalis (24.6 h) and G. mellonella (31 h). The percent larval mortality caused by H. indica alone was resulted significantly more (90% on G. mellonella and 60% on C. medinalis) than S. asiaticum (10% on G. mellonella and 40% on C. medinalis). Progeny produced by H indica and S. asiaticum was significantly more (84134 and 80458 IJs/larva respectively) on G. mellonella than they produced on C. medinalis larva (4843 and 4330 IJs/larva respectively). The combined use of entomopathogenic nematodes may offer an integrated approach to increase the efficacy of control of the rice leaf folder, Cnaphalocrosis medinalis and it could be a viable component in the Integrated Pest Management (IPM) where other control measures are ineffective or cannot be imposed.