Sixty-four sorghum accessions were screened for resistance to the grain midge, Contarinia sorghicola Coq., under natural infestation conditions at Tamil Nadu Agricultural University, Coimbatore during 1982. Absolute resistance was not found in any of them. Low grain damage was recorded in PVK 50 (6.61%), PVK 55 (11.58%), AF 28 (17.03%) and DJ 6514 (17.05%) while the susceptible accession, SPV 234 recorded high grain damage (92.72%) in the screening trial. The ovipositional preference studies at insectary revealed significantly reduced grain damage in the resistant accessions. Among them, the lowest damage (8.33%) was recorded in PVK 50 followed by AF 28, DJ 6514 and PVK 55 while the susceptible accession, SPV 234 recorded 21.57% grain damage. In the choice experiments, SPV 234 had 11.22–35.36% more infestation than in the resistant accessions evaluated along with it. Studies on development and biology of the midge revealed that antibiosis is one of the mechanisms of resistance in the lines, PVK 50, DJ 6514, AF 28 and PVK 55.
