Evaluation of Pathogenicity and In Vivo Mass Production of Entomopathogenic Nematodes

Pathogenicity of five native entomopathogenic nematodes (EPNs) viz., Steinernema masoodi, S. seemae, S. mushtaqi, S. carpocapsae and O. amsactae were tested against final instar larvae of pod borer Helicoverpa armigera, legume pod borer, Maruca vitrata, tobacco caterpillar, Spodoptera litura, blue butterfly, Lampides boeticus and red hairy caterpillar, Amsacta moorei. The suitability of these insects for the in vivo mass production of the infective juveniles (IJs) of above tested EPNs species were also evaluated at different temperature (20, 25, 30, 35°C). Among the five species of EPNs, S. masoodi, S. mushtaqi and S. seemae were found most pathogenic to H. armigera, S. litura and L. boeticus as it brought about cent per cent mortality within 48 h, followed by A. moorei (72 h). The other species of EPNs, viz., S. carpocapsae and O. amsactae was the least pathogenic which killed the larvae of S. litura and H. armigera within 96 and 120 h, respectively, while, L. boeticus and A. moorei within 144 h. No mortality of insect was recorded in control. Maximum number of IJs yielded at 30°C followed by 25°C. No multiplication of tested EPN species IJs were recorded at 20°C. Very poor multiplication of all tested IJs was found from A. moorei.H. armigera was found the most suitable host for the mass production of IJs of O. amsactae,which yielded 1.2 X 10⁵ IJs/larva, followed by S. masoodi and S. mushtaqi (1.1 and 0. 91 X 10⁵ IJs/larva, respectively) at 30°C. However, S. litura was the next best suitable alternate host, which produced O. amsactae and S. seemae (0.75 and 0. 61 X 10⁵ IJs/larva, respectively). The present study gives a clue for utilising a suitable EPN, its mass production potential and biological control suitability in insect pests management programme.