EFFECTS OF SOME INSECT GROWTH-REGULATORS ON NATURAL ENEMIES OF SCALE INSECTS (HOM, COCCOIDEA)

We report and discuss effects of four insect growth regulators: buprof ezin, fenoxycarb, pyriproxyfen and chlorfluazuron, at concentrations r ecommended for agricultural use on six species of natural enemies of h omopteran pests. Dipping in buprofezin had no appreciable effect on ad ult mortality, oviposition and development of Comperiella bifasciata ( Howard) (Hymenoptera: Encyrtidae). When exposed to hosts treated with buprofezin, percentage mortality of adult Encyrtus infelix Embleton; ( Encyrtidae) was low, buprofezin had some detrimental effect on immatur e stages of E. infelix when applied prior to parasitization, but not w hen introduced after parasitization. Buprofezin had a slight effect on the immature stages of Cryptochaetum iceryae Williston (Diptera: Cryp tochaetidae), while fenoxycarb and pyriproxyfen had marked detrimental effects on parasitization and/or development of the parasitoid fly. N one of the larvae of Rodolia cardinalis Mulsant (Coleoptera: Coccinell idae) developed into adults after application of buprofezin, fenoxycar b or pyriproxyfen. Buprofezin and chlorfluazuron completely prevented egg hatch of Chilocorus bipustulatus L. (Coleoptera: Coccinellidae). B uprofezin did not adversely affect egg hatch and larval development of Elatophilus hebraicus Pericart (Hemiptera: Anthocoridae); fenoxycarb or pyriproxyfen applied either before or after oviposition on pine nee dles caused total suppression of egg hatch.