Efficacy of Entomopathogenic Nematode, Heterorhabditis indica Against Three Lepidopteran Insect Pests

Pathogenicity of an indigenous entomopathogenic nematode, Heterorhabditis indica was studied against three lepidopteran insect pests, viz. gram pod borer, Helicoverpa armigera, tobacco caterpillar, Spodoptera litura and greater wax moth, Galleria mellonella under laboratory and greenhouse conditions. In laboratory bioassay experiment, the pathogenicity of 2 nd , 3 rd , 4 th and final instars larva was evaluated with 100, 200 and 300 IJs of H. indica/larva exposed for 12 h, 18 h and 24 h period of time. In the green house experiment, it was tested on the larval stages of H. armigera and S. litura spraying nematodes suspension @ 25 ml per plant (at 1000 IJs/ml) on potted cotton leaf. All the stages of larvae of H. armigera, S. litura and G. mellonella were highly susceptible to H. indica however, the degree of susceptibility differed according to instars, dose and periods of exposure. In the dose response bioassay on 2 nd and 3 rd instars larva of H. armigera, S. litura and G. mellonella was resulted more susceptible to 300 IJs of H. indica/larva than 4 th and 5 th instars larvae exposed for 24 h. The percent larval mortality of H. armigera and S. litura on cotton plant influenced by H. indica was significantly more on final instar larva (62.87 and 56.75% respectively) at 60 h of record and it was significantly superior to the other stages of larva.