Control of Red spider mite {Oligonychus coffeae^ Nietner) in tea {Camellia sinensis L. (O) Kuntze] plantation of Barak Valley (Southern Assam) using AUelopathic plant extracts

Abstract

The red spider mite is the most widely distributed and probably the most serious pest of tea in north-eastern India. It also occurs on tea in other parts of India and also in other tea growing countries. Red spider mite normally attacks the upper surface of the mature leaves in which the sap is not flowing freely. In a severe infestation, particularly under conditions of dry weather, the lower surface and the young leaves are almost equally attacked. The affected leaves turn ruddy bronze, and may eventually dry up and fall off. In the present study, varied severity of damage caused by Red spider mite (Oligonychus coffeae, Nietner) was observed in three different seasons i.e. winter, summer and rainy season in the tea growing sub areas of Barak Valley, South Assam. The pest population was found to be seasonally variable and dependent on the prevailing agro-climatic conditions (viz. ambient temperature, rainfall and relative humidity). In the present work allelopathic plant extracts were used to control this pest i.e. Red Spider mite. Among the allelopathic plant extracts used in the experiments for controlling the population of red spider mite in tea Parthenium hysterophorus controlled the pest reasonably well followed by Clerodendrum viscosum, Chromolaena odorata and Ipomea carnea, respectively.