Effect of pesticides on cymbidium orchid pollencap mite and its predator <i>Hypoaspis</i> sp

Abstract

Pots of orchidgrowing media augmented with pollencap mite Tyrophagus neiswanderi and its predator Hypoaspis sp were drenched with carbaryl deltametrin dimethoate and methiocarb to compare their efficacy for mite control with natural predation Mite populations were monitored by heat extraction from 50 ml of potting media on days 0 2 7 and 14 after treatment and compared with water treated controls All pesticide treatments initially reduced pollencap mite numbers (P<005) but after 14 days only methiocarb sustained this reduction to a similar level achieved by the predation of Hypoaspis sp in the controls Dimethoate gave the least effective control of pollencap mite and caused the greatest reduction in Hypoasis sp populations The ability of these four pesticides plus taufluvalinate acephate and methamidophos to reduce movement of pollencap mite was assessed Flower stems (350 mm) with doublesided sticky tape encircling the top were dipped in pesticide and stood in media with pollencap mite After 48 h only methiocarb reduced (P<005) the number of mites moving up the flower stem