EFFECTS OF PRECOCENES (I AND II) AND JUVENILE-HORMONE-I ON SPODOPTERA-LITTORALIS (BOISD.) (LEP., NOCTUIDAE) LARVAE PARASITIZED BY MICROPLITIS-RUFIVENTRIS KOK. (HYM., BRACONIDAE)

Precocenes I & II (PI & PII) and juvenile hormone I (JHI) were topical ly tested on unparasitized and Microplitis rufiventris is parasitized Spodoptera littoralis larvae. Parasitism interferes with normal host r esponse to these compounds, decreasing their effectiveness. In all cas es, the effect was dose-dependent. In contrast to PII or JHI, the lowe r dose of PI was more effective than the higher one. Application of JH I to S. littoralis larvae was less harmful to parasitoid development t han either PI or PII. It is therefore emphasized that the commercial u tilization of insect growth regulators should be undertaken carefully to minimize possible disruptive effects on developing parasitoids.