Evaluation of efficacy of Steinernema feltiae and isolated native strain S. kushidai against Cnaphalocrosis medinalis Guenee

The present study was carried out to compare the efficacy of Steinernema feltiae and native entomopathogenic nematode, S. kushidai against the rice leaf folder, C. medinalis larva at laboratory conditions. Indigenous entomopathogenic nematode was isolated from soil sample collected from Agricultural College and Research Institute, Killikulam and it was identified as S. kushidai KKM strain based on its morphometric measurements. Final instar larvae of C. medinalis were exposed to infective juveniles (IJs) of S. feltiae and S. kushidai under laboratory conditions. LC50 values of S. feltiae on C. medinalis larva were 59.45, 39.42 and 16.04 IJs per larva for the exposure periods of 24, 48, and 72h, respectively. LC50 values of S. kushidai KKM strain were 58.82, 38.11 and 16.67 IJs per ml at 24, 48 and 72 h exposure periods respectively. The LT50 values for C. medinalis larva at different doses viz., 20, 40, 60, 80, and 100 IJs/larva were 66.04, 49.11, 34.68, 32.14 and 24.21 h, respectively. Whereas in case of S. kushidai the LT50 values were 45.42, 41.89, 33.79, 28.33, and 22.30 hours at 20, 40, 60, 80, and 100 IJs per larva, respectively.