The efficacy of insecticides for the control of Nezara viridula (L.) (Hemiptera: Pentatomidae), the green vegetable bug, was tested in laboratory and field trials. Bioassays of 11 insecticides against field-collected adults were used to select two insecticides for a field experiment conducted in a process sweet corn crop, Zea mays (L.) (cv. Punch), near Tolaga Bay on the east coast of the North Island, New Zealand. Lambda-cyhalothrin (as 200 ml Karate(R)/100 litres water ha(-1)) and methamidophos (as 1 litre Tamaron(TM)/100 litres water ha(-1)) were tested against a water control. Both insecticides demonstrated efficacy, with respective mortality rates of 87 and 83% compared with 2% in the control. Green vegetable bug flew into the experimental crop in large numbers over 48 h before the start of the trial. Damage thresholds were exceeded in two of the three control plots within 7 days of the green vegetable bug first invading the crop, leaving only a very small 'window' for insecticide application. Success or otherwise of these insecticides is therefore likely to be dependent on the timing of application as well as on the efficacy of the products themselves.