ACTIVITY OF SOME PYRETHROIDS AGAINST PERIPLANETA-AMERICANA AND BLATTELLA-GERMANICA

The knockdown and contact killing actions of various pyrethroids were compared using Blattella germanica and Periplaneta americana. A wide range of knockdown activity was found; 5‐benzyl‐3‐furylmethyl (1R)‐cis‐3‐(dihydro‐2‐oxo‐3‐thienylidenemethyl)‐2,2‐dimethylcyclopropanecarboxylate (RU 15525) acted fastest, more rapidly than pyrethrins, against B. germanica as well as having a low LD50 value. Topical application and direct spray tests showed that (S)‐α‐cyano‐3‐phenoxybenzyl (1R)‐cir‐3‐(2,2‐dibromovinyl)‐2,2‐dimethylcyclopropanecarboxylate (NRDC 161) was more active as a killing agent, by an order of magnitude, than cismethrin, the next most active compound, and also had considerable knockdown activity. Piperonyl butoxide generally had little synergist effect. Female P. americana were over three times more tolerant than males to a range of insecticides applied topically. Residual knockdown action in the WHO resistance test was observed to provide baseline data. There was little overlap in speed of action between pyrethroids and other insecticides among the compounds tested. Copyright © 1979 John Wiley & Sons, Ltd