Diamondback moth (DBM); Plutella xylostella (L.) (Lepidoptera: Yuponomeutidae) is a major pest of cabbage throughout the world. Several bio-pesticides have been tested for the management of DBM in different parts of the country, but only few have shown promising results. Amongdifferent bio-agents, entomopathogenic nematodes were found comparatively better over others insuppressing the population of diamondback moth (DBM). Laboratory and field studies were carriedout to evaluate the efficacy of an indigenous population of Steinernema carpocapsae against fourthinstar larvae of diamondback moth. In laboratory conditions the efficacy of EPN was tested at four dosages viz., 250, 500, 750 and 1000 IJs/petri plate. The per cent mortality of DBM larvae after 72hours was recorded, maximum 100 % with an inoculum level of 1000 IJs/petri plate followed by 85% 76.17 %, and 71.84 % at 750, 500 and 250 IJs/ petri plate respectivel at 72hrs. The comparativeefficacy of different formulations of entomopathogenic nematode, S. carpocapsae was also testedagainst diamond back moth (P. xylostella) infesting cabbage in field conditions with different inoculum levels (doses) of 20 lakh and 30 lakh IJs /plot. The maximum (53.75) per cent mortalityof DBM was recorded at 30 lakh IJs/ plot with an antidesiccant liquid paraffin 1% after 7th day of

application in the field conditions.