Anti-mite activity of Polygonum hydropiper L. (Polygonaceae) extracts against tea red spider mite, Oligonychus coffeae Nietner (Tetranychidae: Acarina)

Abstract

Acaricidal, antiovipositional and ovicidal activities of Polygonum hydropiper (Polygonaceae) against tea red spider mite, Oligonychus coffeae (Nietner) (Tetranychidae: Acarina) were studied under laboratory conditions. Essential chemicals of P. hydropiper obtained from crude extracts of both water and petroleum ether/acetone/methanol fractions by following cold percolation and sequential extraction methods on the basis of solvents' polarity. Ovicidal activity of P. hydropiper was observed only in petroleum ether and acetone fractions. High acaricidal activity were observed in acetone followed by petroleum ether fraction, methanol and finally by water fractions. The effect was stronger with increasing concentrations. Antiovipositional property was evident only at higher concentrations of P. hydropiper. Availability and distribution of this weed (P. hydropiper) in and around tea growing areas of sub-Himalayan region, along with its processing for the feasibility of including P. hydropiper extracts in the current integrated pest management program of tea red spider mite, are discussed. The name and address of the institution where the work was done: Entomology Research Unit, Department of Zoology, University of North Bengal, Darjeeling-734 430, West Bengal, India.