Effect of acaricides on eggs and subsequent development of tea red spider mite, oligonychus coffeae neitner

The tea red spider mite, Oligonychus coffeae Neitner (Acarina: Tetranychidae) is one of the major pests of tea in North East India causing 17-20% crop loss annually. Acaricides having ovicidal action are of great importance to manage this pest as they also limit the next progeny. Consequently nine acaricides, viz., propergite 57 EC, hexythiazox 5.45% EC, spiromesifen 240 SC, fenazaquin 10% EC, etoxazole 10%EC, ethion 50 EC, fenpyroximate 5EC dicofol 18.5 EC Sulphur 80 WG, recommended for use in tea in India were evaluated for their ovicidal action as well as their effect on subsequent development of Oligonychus coffeae under the laboratory conditions. Propergite 57 EC, hexythiazox 5.45% EC, spiromesifen 240 SC, fenazaquin 10% EC and etoxazole 10%EC showed cent per cent egg mortality when treated at their recommended dosages. The ovicidal activity exhibited by ethion, fenpyroximate and dicofol were 64.8, 57.9 and 21.3 per cent respectively. Sulphur 80 WG however did not show any ovicidal activity. Adult emergence was significantly reduced compared to 92% in the control. Thus the tested acaricides can alternately be used for effective and sustainable management of red spider mite in tea plantation.