Toxic Effects of Synthetic Juvenile Hormones on Several Aphid Species12

Abstract

Nine synthetic juvenile hormone mimics were screened as toxicants against the pea aphid, Acyrthosiphun pisum (Harris), and the raspberry aphid, Amphorophora agathonica (Hottes). First- and second-instar and adult aphids exposed to plant material dipped in 0.1% hormone solutions indicated that certain structures were most toxic to the pea aphid (Hoffman-LaRoche RO 8-4314 and Stauffer R 20458) while others were essentially nontoxic (Hoffman-La Roche RO 20-3600) or almost equitoxic (Zoecon ZR-512) to both species. Feeding eight different aphid species on plant material dipped in 0.1% Zoecon ZR-512 gave a mortality range of 18% for the turnip aphid, Hyadaphis psendobrassicae (Davis), to 73% for the pea aphid. Exposure to lower levels of hormone did not always produce direct toxic results but did yield a wide range of morphological abnormalities and considerably altered reproduction.