Enhanced Acaricidal Activity of Senna auriculata and Ocimum tenuiflorum Extracts with the Addition of Adjuvant against Red Spider Mite, Oligonychus coffeae Nietner (Acarina: Tetranychidae) Infesting Tea

Abstract

Tea ( Camellia sinensis ) is one of the most consumed non-alcoholic beverages in the world and has been affected by many pests which damage its quality and production globally. In this paper an attempt has been made to evaluate the aqueous leaf extracts of Senna auriculata and Ocimum tenuiflorum with and without adjuvant for their effect on red spider mite (RSM), Oligonychus coffeae (Nietner) infesting tea. Resulting, Senna auriculata, leaf extracts with adjuvant caused 90 % (LC 50 :1.21 and LC 90 :2.33 %) mortality which was greater compared to Ocimum tenuiflorum whereas 73 % (LC 50 :1.40 and LC 90 :2.81 %) was observed at 5 % concentration after 24 h exposure and very lowest mortality percent were observed both extracts without adjuvant. Ocimum tenuiflorum leaf extracts with adjuvant (0.05 %) showed highest ovicidal activity and effective ovipositional deterrence compared with S. auriculata treatment. The evaluated plant extracts with adjuvant are effective for controlling RSM and it could be an alternative, easily accessible, and eco-friendly approach for control of mite infesting tea.