Effects of sugar/flour spheres coated with paint and insecticide on alighting female Ceratitis capitata (Diptera: Tephritidae) flies

We studied the behavior and fate of mature, wild-origin Ceratitis capitata (Wiedemann) females allowed to feed on 7-cm-diam spheres comprised of a mixture of sugar, flour and glycerin and coated with yellow latex paint containing either no insecticide, dimethoate (1.5% a.i.) or imidacloprid (1.5% a.i.). Females feeding on imidacloprid-treated spheres for 20 sec exhibited very little tendency to forage within host plants or to lay eggs either shortly after or 24 h after feeding, and suffered high mortality within 48 h. In contrast, females feeding on dimethoate-treated spheres for 180 sec exhibited, shortly thereafter, a tendency to forage within host plants and to lay eggs about equal to that of females feeding on untreated spheres, although they suffered high mortality within 24 h. In a field test, imidacloprid-treated sugar/flour spheres provided a significant level of protection of fruit from oviposition by C. capitata during 24 h periods (equal to that provided by sticky yellow spheres), whereas dimethoate-treated spheres did not. Further research on long-term activity of pesticide residue and on sphere performance under natural conditions will be necessary, however, before sugar/flour spheres coated with yellow latex paint and insecticide can be recommended for control of C. capitata.