Efficacy of Acaricides Against <i>Oligonychus coffeae</i> on Tea and their Effect on Natural Enemies

Red spider mite, Oligonychus coffeae Nietner is a serious problem of tea causing significant economic loss to the tea industry. Farmers depend on synthetic acaricides for its management. Despite such routine application of acaricides, there are some reports of poor efficacy of acaricides at the recommended doses. The ineffective acaricides need to be replaced with the effective one. Hence, an experiment was conducted during March-April, 2018 and 2019 with the objectives to evaluate the efficacy of seven acaricides as well as to study their effect on natural enemies. The experiment was laid out in randomized block Design (RBD) with eight treatments including control. Based on the results of the two years of study, cyflumetofen 20SC @ 125g a.i/ ha was found to be the best acaricide followed by spiromesifen 22.9SC @ 96 g a.i/ ha. Both the acaricides resulted more than 90% reduction during the period of experiment. These two acaricides also showed less impact on spiders and coccinellids.