INDUCTION OF WING TWISTING ABNORMALITIES AND STERILITY ON GERMAN COCKROACHES (DICTYOPTERA, BLATTELLIDAE) BY A JUVENOID PYRIPROXYFEN

Contact activity of pyriproxyfen, evaluated on 4th-instar nymphs of Ge rman cockroach, Blattella germanica (L.), was found to be effective in inducing morphogenetic wing deformation abnormalities on both sexes o f the cockroach. A dose-response study based on a rating system for mo rphological wing deformations in adults after exposure to pyriproxyfen showed that the 50% effective dose (ED(50)) for wing twisting effects in male and female B. germanica were 0.4-0.5 and 0.4-0.7 mg (AI)/m(2) , respectively. There was a good correlation between physical wing twi sting effects in adults induced by pyriproxyfen and inhibition of repr oduction (correlation coefficient, r = 0.98). The 50% sterility dose ( SD50) of pyriproxyfen against the German cockroaches was 0.05 mg (AI)/ m(2). Of the portion of cockroaches unaffected by pyriproxyfen, the oo thecal incubation period and sex ratio of the offspring appeared norma l.