Elimination of population of the Oriental cockroach (Dictyoptera: Blattidae) in a simulated domestic environment with the insect juvenile hormone analogue (S)-Hydroprene

Two mixed (seminatural) populations of the Oriental cockroach, Blatta orientalis (L.), were established in identical artificial domestic environments contained inside converted steel freight containers. After a 10-wk period of acclimation, during which the populations were monitored with Roatel traps, one population was treated with an aerosol formulation (total release fogger) containing 290 mg of the juvenile hormone analogue (S)-hydroprene. The other (control) population was treated with aerosol propellant only. These treatments were repeated at approximately 6 monthly intervals for the duration of the experiment. Changes in these populations were monitored for a period of 28 mo by regular trapping with live-catch Roatel traps. On each occasion, trapped insects were counted, sexes were determined, nymphs were assigned to one of three arbitrary size categories (small, medium, or large), and adults were examined for external morphological deformities. At monthly intervals, 20 adult females also were randomly selected from the trapped insects and confined with several trapped males, and a record of ootheca production and viability was kept. During the first 6 mo of the experiment, both populations showed a general increase. Subsequently, the population in the control environment remained high for the duration of the experiment. In contrast, the population in the environment treated with hydroprene gradually declined and was eradicated after 26 mo. Elimination of the treated population resulted directly from the inhibition of reproduction in adult cockroaches that had been exposed to hydroprene during the latter stages of nymphal development. These results indicate that the juvenile hormone analogue (S)-hydroprene has considerable potential for use as a control agent against populations of Blatta orientalis infesting industrial, food manufacturing, and domestic premises.