Antibiotic effect of sorghum genotypes IS-61 and IS-353 was identified perhaps for the first time. Various ecobiological parameters studied in comparison with popular CSH-5 sorghum hybrid clearly indicated significant degree of antibiosis especially in larval survival (49 to 68%), larval length (30.3 to 34.9 mm), larval weight (248 to 346 mg), pupal (13.8 to 16.1mm), larval weight (209 to 265 mg), pupal period (9.1 to 9.6 days), adult emergence (38 to 65%), fecundity (268 to 408 eggs/female) add egg viability (49.77%).