Biocontrol Potential of Distolabrellus veechi isolate KPI (Nemata: Rhabditida)Against Cotton Cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

Spodoptera litura, Fabricius (1775) larva is voracious feeder and cause huge damage to many crops and vegetables. Its management has become increasingly difficult as it has developed resistance to many organic pesticides. Mostly, bio-control agents are eco-friendly, specific and safe. Among nematodes, two families, Steinernematidae and Heterorhabditidae are popular for control of many insect pest populations. But free living nematodes having potential to control insect population are not much characterized. We identified a free living soil dwelling nematode Distolabrellus veechi isolate KPI (Parihar et al., 2016) which showed pathogenic properties. It was isolated from the soils of Kishanpura Punjab in India and reared on Galleria mellonella, Fabricius (1798) in laboratory conditions. Its efficacy against S.litura and immune response of S. litura was also studied. Bioassay studies showed that the phenoloxidase activity first decreased followed by an increase as compared to control with increase in exposure time against nematode infection. Prohaemocytes count decreased where as granulocytes and cell necrosis increased as compared to control with increase in time after nematode inoculation; the larvae stop feeding, got paralyzed and finally died. 100% mortality was observed in all the three instars of S. litura at different time intervals and at different concentrations.