none Bactrocera cucurbitae; Bactrocera dorsalis; Ceratitis capitata; REPRODUCTIVE-PRODUCTIVITY; LONGEVITY-; Insecticide effects; EMERGENCE-; Eclosion, effects of insecticides; HYMENOPTERAN-PARASITES; Braconidae; Insecticide effects on host & parasite eclosion, longevity & reproduction; FERTILIZERS-AND-PESTICIDES; Cyromazine & diazinon effects on host & hymenopteran parasite biology Diachasmimorpha longicaudata; Diachasmimorpha tryoni; REPRODUCTIVE-PRODUCTIVITY; Insecticide effects, dipteran hosts Diachasmimorpha; Psyttalia; LONGEVITY-; Insecticide effects; EMERGENCE-; Eclosion, effects of insecticides; DIPTERAN-HOSTS; Tephritidae; Insecticide effects on host & parasite eclosion, longevity & reproduction; FERTILIZERS-AND-PESTICIDES; Cyromazine & diazinon effects on dipteran host & parasite biology. Effects of cyromazine and diazinon on eclosion, longevity, and reproduction of Mediterranean fruit fly, Ceratitis capitata (Wiedemann); oriental fruit fly, Bactrocera dorsalis (Hendel); and melon fly, B. cucurbitae (Coquillett), were determined. Eclosion and longevity of the braconid endoparasitoids Psyttalia incisi (Silvestri), P. fletcheri (Silvestri), Diachasmimorpha longicaudata (Ashmead), and D. tryoni (Cameron) and the reproduction of D. longicaudata and D. tryoni that parasitized fruit flies exposed to cyromazine and diazinon were also determined. Formation of puparia was not affected by cyromazine but was affected by diazinon in a concentration-dependent manner at the concentrations tested. At LC-50 B. dorsalis and B. cucurbitae were more susceptible to cyromazine than to diazinon; C. capitata was equally susceptible to both chemicals. Eclosion of endoparasitoids from diazinon-treated hosts was concentration-dependent, but parasitoid eclosion from cyromazine-treated hosts was not significantly different from that of controls. Fecundity and fertility of B. cucurbitae were significantly reduced in females that survived treatment with 0.5 ppm cyromazine. Production of F-1 progeny by D. tryoni that eclosed from flies exposed to 1.0 ppm diazinon was significantly reduced. Cyromazine had no impact on progeny production of either D. longicaudata or D. tryoni at the concentrations tested. Potential use of cyromazine in conjunction with biological control for fruit fly eradication and control programs is discussed.