During the course of survey, two natural biotic factors, viz. parasitoids Cotesia flavipes Cameron, Bracon chinensis (Szepligeti) and Stenobracon sp. and a pathogen Bacillus thuriengiensis Berliner were found to regulate the larval population of Chilo partellus (Swinhoe) in the field. Among the parasitiods, C. flavipes was the most predominent. The impact of biotic factors was more pronounced during September when 44.8 per cent mortality of the host larvae was recorded. Nutrition; Diet; Parasites diseases and disorders; Parasites; Insect parasites; Diseases and disorders; Diseases; Microbial diseases; Ecology; Population dynamics; Habitat; Man made habitat; Land and freshwater zones; Oriental region Chilo partellus (Pyralidae); Food plants; Sorghum; Hymenopteran parasites; Bracon; Cotestia & Stenobracon; Bacterial diseases; Bacillus thuriengiensis; Population regulation; Cultivated land habitat; Sorghum fields; India; Population regulation by natural enemies, crop field survey none