Journal of Environmental Biology

Response of native entomopathogenic nematode, Steinernema spp. (TFRIEPN-57) isolated from central India to variation in temperature and soil moisture

Nitin Kulkarni*, Vinod Kumar Mishra, Smita Daksh and Sanjay D. Paunikar

Forest Entomology Division, Tropical Forest Research Institute, Jabalpur- 482 021, India

*Corresponding Author E-mail: kulkarnin@icfre.org

Publication Data

Paper received:

20 May 2015

Revised received:

17 August 2015

Accepted:

21 October 2015

Abstract

The paper reports effect of temperature and soil moisture on horizontal or vertical dispersal by infective juveniles (IJs) of native entomopathogenic isolate, Steinernema sp. (TFRIEPN-57) from central India. The observations recorded 72 hrs after exposure of IJs to eleven temperature regimes (0, 5, 10, 15, 27, 30, 32, 34, 36, 38 and 40 0C) revealed survival of IJs from 10 to 36⁰C temperature, below and above which, there was 100% mortality. Within the above range, IJs exposed to 10⁰C and 36⁰C showed 88.59% and 55.41% survival, respectively. Exposure of IJs to 0⁰C revealed no survival at and above 12 hrs, whereas 5⁰C allowed survival up to 48 hrs. IJs exposed to temperature extreme of 380C exhibited 38.98% survival up to 8 hrs. Soil moisture of 10% proved suitable for horizontal dispersal of IJs towards the G. mellonella larvae embedded in soil 30 cm away from the point of release in 72 hrs. There was no horizontal dispersal beyond 30cm. However, the IJs exposed to soil moisture of 10 and 15% displayed vertical dispersal up to 40 cm towards embedded G. mellonella larvae in 72 hrs. Multiple regression analysis of the data showed that infectivity in embedded G. mellonella larvae at various horizontal and vertical distances from the point of release of IJs had significant positive correlation with soil moisture and exposure time and significant negative correlation with distance.?

 Key words

Dispersal, EPN, Forest insect pests, Galleria mellonella, Infective juveniles, Native populations, Steinernema

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