Terminalia chebula Retz. (Combretaceae): source of a botanical acaricide against Oligonychus coffeae Nietner (Acarina: Tetranychidae)

Abstract

Aqueous extract of the dry pericarp of the fruits of Terminalia chebula was evaluated in the laboratory against the tea red spider mite, Oligonychus coffeae (Nietner) to determine its effect on mortality of adult mites, viability of eggs and oviposition deterrence. The same extract was also evaluated in the field to determine its effect on mite populations. A direct spray method was used in the laboratory at concentrations of 1%, 2%, 3%, 4%, 5%, and 6%. Mortality of O. coffeae was dependent on both concentration and time after application. Deposition of eggs by adult mites on treated leaf surfaces decreased significantly and the viability of eggs was also significantly reduced. No phytotoxic effect was observed when tea bushes were sprayed with different doses of aqueous extract of the dry pericarp of the fruits of Terminalia chebula. Tea samples were taint free. Quality (appearance of liquor, flavour, taint, and taste) of tea was not adversely affected by treatment with the extract. With the easy availability and distribution of T. chebula in and around the tea-growing areas of north east India, along with its processing for economic utilization, it may be incorporated in current integrated pest management programmes of tea.