Effect of Salinity on an Entomopathogenic Biocontrol Nematode, Hetrorhabditis indica

Entomopathogenic nematodes, especially ICRI-18, a strain of Heterorhabditis indica, are being used as efficient biological control agent for a sub-terranean pest called Basilepta fulvicorne affecting cardamom plant ischolar_mains. The cardamom plantation has been spread over the western ghats of south India where H. indica (strain ICRI-18) is used for the control of ischolar_main grub. Salinity plays a significant role in microbial interactions and all inhabitants of soil. As the method of irrigation varies from place to place so does the salinity of water and soil. As salinity plays a key role in survival of soil organisms, the aim behind the present study was to investigate the compatibility of the bio-control agents with salinity. The effect of sodium chloride over H. indica at various concentrations (0.1M to 0.5M) was evaluated. The observations revealed that salinity did cause a proportional mortality to that of salt concentration. However, more than 80% of nematodes survived up to 0.3M concentration, after which there was a drastic reduction of the nematode population. The nematode population reduced at 0.4 M considerably, which can be concluded that salinity of the soil at cardamom plantations did not cause any adverse effect on the nematodes.