Cyromazine Effects on the Reproduction of Anastrephaludens (Diptera: Tephritidae) in the Laboratory and in the Field

The effects of cyromazine on the adult Mexican fruit fly, Anastrepha ludens (Loew), include mortality and reduced fecundity and survival of the F1 generation. Dosage-dependent mortality was recorded for concentrations from 0.125 to 16%. Neonate to 2-d-old females fed an artificial diet with 5% cyromazine were incapable of laying eggs in fruit with a resistance of penetration >11 newtons. Laboratory observations showed that treated females could not insert their ovipositor into grapefruit rind. When the same females were given a soft substrate (parafilm membrane), they laid significantly fewer eggs than control females. The F1 generation of treated females developed significantly less in an artificial larval diet and in grapefruit in the field. A field test showed that grapefruit from treatments made with 5% cyromazine-NuLure mixture had significantly fewer larvae per fruit than the control. This difference did not occur with fruit from a 5% malathion treatment.