TOXICITY OF POGOSTEMON PARVIFWRUS (BENTH) AND POLYGONUM HYDROPIPER (L) ON DEVELOPEMETAL STAGES OF RED SPIDER MITE (OLIGONYCHUS COFFEAE, NEITNER) (ACARINA: TETRANYCHIDAE) ON TEA

摘要

A study was conducted during 2009-10 to assess the toxicity of chloroform extracts of Pogostemon parviflorus (Benth.) and Polygonum hydropiper (L) against red spider mite (Oigonychus coffeae, Neitner) under laboratory condition using leaf detached method. Both the plant extracts possesed the acaricidal properties on developmental stages of red spider mite. The treatment with both plant extracts exhibited prolonged developmental period which affected the population build up of the pest in subsequent generation. The efficacy of extracts was found to be dose dependent. However, except in deutonymph the duration was found to be reduced at lower dose with Pogostemon parviflorus extracts then the normal but, the result was not significant. It is also observed that high toxicity to the mite was exhibited by Polygonum hydropiper.