Infectivity of entomopathogenic nematodesHeterorhabditis andSteinernema spp. to sugarcane shoot borer (Chilo infuscatellus snellen) at different temperatures

Abstract

Infectivity of twenty nine entomopathogenic nematode (EPN) isolates belonging to the families of Heterorhabditidae and Steinernematidae to sugarcane shoot borerChilo infuscatellus Snellen was investigated at 18 and 27°C under laboratory conditions. Although all the EPN isolates tested caused mortality of shoot borer larvae, there were differences in the level of mortality. Among the EPN isolates tested at 27°C, 120 h after inoculationHeterorhabditis indica (LN2),H. bacteriophora (German isolate) andSteinernema glaseri (Australian isolate) caused 100 per cent mortality of shoot borer larvae. Average time taken to kill shoot borer larvae was least (22.8 h) in case ofH. indica (LN2) followed byS. glaseri (26.5 h) andH. bacteriophora (German isolate) (28.4 h). Mortality percentage for other isolates ranged from 39.9 to 86.6. At 18°C,S. glaseri (Australian isolate) andH. bacteriophora (German isolate) caused 100 per cent mortality 120 h after nematode inoculation; with an average time taken to kill shoot borer larvae of 41.2 and 42.6 h respectively. All the EPN isolates took less time to cause mortality of shoot borer larvae at 27 than at 18°C. The multiplication of EPN in shoot borer larvae infected at 27°C was comparatively more than those infected at 18°C.