Survival and Virulence Capacity of Native Strain of Entomopathogenic Nematode, Steinernema cholashanense in Different Formulations

Abstract

Experiments were conducted to assess the survival and virulence of an indigenous strain of entomopathogenic nematode, Steinernema cholashanense MH128155 in sponge, vermiculite and cadaver formulations. Maximum recovery of infective juveniles (IJs) was from vermiculite formulation (96.26%), followed by sponge formulation (91%) in the first month stored at 15 °C. IJs recovery in the second month decreased to 90 and 73.4% in vermiculite and sponge formulation, respectively. At 20 °C storage, the recovery of IJs from vermiculite formulation was 95 and 87% and from sponge, 88.10 and 67.24% in the first and second month, respectively. A sharp decline in nematode population was noticed in the third and fourth month at both 15 and 20 °C. The cadaver formulation stored at 15 °C yielded 1.93 lakh IJs as compared to 1.70 lakh IJs at 20 °C in the first month. In case of vermiculite and cadaver formulations, the virulence potential of IJs against rice moth, Corcyra cephalonica larvae was maximum in the first two months, resulting in approximately 100% larval mortality, but per cent larval mortality gradually decreased in the third and fourth month at 15 and 20 °C, whereas IJs formulated in sponge caused 100% larval mortality in the first month which in the second month decreased to 86 and 75% at 15 and 20 °C, respectively. The storage temperature and virulence capacity of S. cholashanense MH128155 were comparatively better at 15 °C than 20 °C; however, storage and virulence of IJs in vermiculite were superior over cadaver and sponge formulation.