SELECTION OF COMPOUNDS ACTING AS APHID DEVELOPMENT AND REPRODUCTION REGULATORS - LABORATORY SCREENING

Newly synthesized compounds were examined in screening tests with the pea aphid, Acyrthosiphon pisum (Harris) for juvenilizing effects, usin g the spray-residue method. Two derivatives of 2-(4-hydroxybenzyl)cycl ohexanone bearing a carbamate or an ether group were found to be the m ost active inhibitors of development and reproduction. Tests with the hop aphid, Phorodon humuli (Schrank) of insecticide-susceptible and mu lti-resistant biotypes and with the green peach aphid, Myzus persicae (Sulzer) confirmed their biological activity. Cross-resistance between conventional insecticides and juvenoids was not indicated. The format ion of supernumerary larvae, where retention of larval cauda and corre sponding larval characters were observed and reproduction was entirely suppressed, was recognized as the critical result of the juvenilizing effect. The production of viable progeny was not affected in those ap hids which survived treatment and developed normal adult external geni talia.