Influence of Two Acaricides on Survival of Predator <I>Blaptostethus pallescens</I> (Poppius) (Hemiptera:Anthocoridae)

Abstract

Experiments were conducted to find out the influence of two acaricides (Propargite and Ethion) on survivability of an anthocorid predator, Blaptostethus pallescens (Poppius) when exposed at different time intervals under laboratory conditions. In present investigation, the second instar nymphs of B. pallescens were exposed to propargite @ 300 ml/acre and ethion @ 450 ml/acre for different time intervals using two methods of treatment viz; leaf disc and foliar spray method. Both the acaricides had adverse effect on the survival of the predator but the effect of ethion was faster as compared to propargite. When exposure time for ethion treatment was increased from one to six hours, the mortality of second instar nymphs increased from 0.10 to 86.00 per cent. On the other hand, in case of propargite, the mortality was 0.10 per cent at 1 hour interval and gradually increased with increase in exposure time, up to 20 per cent at 48 hours of exposure. Second instar nymphs were released on potted plants showed higher rate of mortality after the foliar spray of acaricides as compared to those in leaf disc where corrected per cent mortality of ethion treated nymphs was 10.96 per cent at one hour of exposure and it became almost 100 per cent at six hours of exposure or above. Similar trend was followed in case of propargite where mortality was 6.97 to 75.5 per cent, when exposure time increased from one hour to 12 hours. Thus both acaricides were found to be unsafe to B. pallescens .