Efficacy of some entomopathogenic nematodes against insect pests of ginger and their multiplication

Abstract

The efficacies of eight native entomopathogenic nematodes (EPNs) were tested against larvae of hairy caterpillar, Euproctis sp., and larvae and pupae of the shoot borer, Conogethes punctiferalis, and their multiplication was assessed. The penetration of these nematodes in the shoot borer larvae was also assessed. Of the tested EPNs, all isolates, except IISR 08 of Oscheius sp., caused 100% mortality to larvae of hairy caterpillar. Heterorhabditis sp. (IISR 01), Steinernema sp. (IISR 02) and Oscheius sp. (IISR 07 and 08) caused 100% mortality also to shoot borer larvae. Oscheius sp. (IISR 07) was the most virulent against the shoot borer pupae, causing 100% mortality, followed by Steinernema sp. (IISR 02) and Oscheius sp. (IISR 05) which killed 67% of the pupae. The multiplication of infective juveniles (IJs) of EPNs was greater in shoot borer larvae than in hairy caterpillar. The greatest number of infective juveniles was observed for Steinernema sp. (IISR 02) followed by Oscheius sp. (IISR 05), with the fewest found in Steinernema sp. (IISR 03) and Oscheius sp. (IISR 07) (10,432 and 14,373 IJs/ larva, respectively). The largest number of IJs that penetrated into shoot borer larvae (15.5 IJs/larva) were of Steinernema sp. (IISR 03) followed by Heterorhabditis sp. (IISR 01), and the fewest (2.8 IJs/larva) were of Oscheius sp. (IISR 08).