The efficacy of aldicarb against the aphid Lipaphis erysimi on radishes was compared with that of a standard application of 0.08% malathion in field studies in Haryana, India. Treatments of aldicarb were by dipping stecklings in 0.2% aldicarb slurry or by soil application at 1.0 kg a.i./ha either as a split dose (half at planting and half at pest appearance) or a full dose (all at pest appearance). Plots treated with the split dose application of aldicarb had the lowest incidence of L. erysimi and the greatest yield. The cost-benefit ratios of the steckling treatments, the split dose and full dose soil applications of aldicarb and the treatment with malathion were 83.8, 34.5, 26.6 and 14.7.