Effect of Ultra Violet (UV) radiation protectants on indigenous isolates of entomopathogenic nematode, Steinernemadharanaii (Nematoda: Steinernematidae)
Sanjay Paunikar, Nitin Kulkarni
The paper reports the effect of Ultra-violet (UV) radiation on the survival and pathogenicity of new species of EPN, Steinernema dharanaii (TFRIEPN-15) in the laboratory. To investigate the effects of ultraviolet radiation exposure on S. dharanaii was taken with to PABA (Para Amino Benzoic Acid) and Ranipal (optical brighteners). The study was conducted on the effects of the survival (50 Hz-220 V) Ultra-Violet (UV) radiation for different time lengths (30, 60 min, 2, 4, 6, 16 and 24 hours. The pathogenicity of exposed EPN infective juveniles (IJs) to waxmoth larvae, Galleria mellonellawere tested under laboratory conditions. The result showed that the exposure of IJs to UV radiation in presence of 0.05 and 0.1% PABA for 30 min. indicated no immediate effect after evident by 100.0% survival at par with control without PABA (P>0.05). However, when the same batch of IJs was observed 12 and 24 hrs after exposure, time-dependent and decrease in survival was noted. The IJs exposed to UV light in presence of PABA did not show any deleterious effect on infectivity potential. The infectivity after 24hrs was at par with control unexposed to UV (P>0.05). The exposure of IJs to UV radiation in presence of 0.05 and 0.1% Ranipal® for 30 min. indicated no mortality effect after exposure, evident by 100.0% survival at par with control (P>0.05). Unlike PABA, there was no mortality observed even when the same batch of IJs were observed 12 and 24 hrs after exposure (P>0.05). There was 100.0% infectivity noted in all the IJs exposed to UV in presence of Ranipal®. These findings will shed more light on using locally isolated entomopathogenic nematodes under ultraviolet radiation stress with different protectants.