Novel acaricide toxicities on Tetranychus urticae infesting Piper betle

Laboratory and field experiments were conducted to test novel acaricide efficacies for the management of twospotted spider mite, Tetranychus urticae (Koch) on betelvine (Piper betle L.). The treatments were abamectin 1.9EC @ 0.3ml, 0.5ml and 0.7ml/l, propargite 57EC @ 2.5 and 3.0ml/l, fenazaquin 10EC @ 1.7ml/l, fenpyroximate 5EC @1.25ml/l, spiromesifen 22.9SC @ 0.8ml/l, and compared with conventional compounds, sulphur 80WDG @ 3g/l and dicofol 18.5EC @ 2.5ml/l. In laboratory studies, all the acaricides resulted in 14.47 to 85.53% mortality with highest in abamectin @ 0.7ml/l during I season and lowest in dicofol, whereas in II season lowest per cent mortality of 21.80 was recorded in sulphur and highest mortality of mites (83.40%) was noted in abamectin @ 0.7ml/l at 72h after treatment. The acaricides caused mortality of mites in the range of 16.27 of 90.98% during 10 day observation period in the field studies with highest in abamectin (0.7ml/l) treated plots followed by fenazaquin (59.44% at 10th day) and least mortality was showed by dicofol, i.e. less than 20% in first season but spiromesifen, fenpyroximate and propargite @ 3.0ml/l showed good efficacy, i.e. 51.40%, 46.37% and 40.37% mites mortality, respectively, at 10th day during I season trial. In II season, lower mortality of mites was recorded in dicofol (34.41%–16.99%) and sulphur (38.03% – 19.57%) on 1st and 10th day, respectively indicating that these acaricides lost their efficacy over a period of time but abamectin @ 0.7ml/l (90.35–70.39%) and 0.5ml/l (85.65–65.71%) throughout the observation period showed higher efficacy followed by fenazaquin (72.24–56.86%), spiromesifen (69.13–48.60), propargite @ 3ml/l (60.80–39.76%) and fenpyroximate (48.84–28.43%) at 1 and 10th day after spray observations. Abamectin and fenazaquin were superior over other acaricides tested under both conditions followed by spiromesifen, fenpyroximate and propargite.