Life history of Parafreutreta regalis (Diptera: Tephritidae): a candidate agent for biological control of Delairea odorata.

Cape-ivy, Delairea odorata Lamaire, is an ornamental vine, native to the eastern part of South Africa, which has escaped into natural areas in many countries and become a serious pest. Exploratory surveys in South Africa located several potential biological control agents. One of these is Parafreutreta regalis Munro, a tephritid fly that causes large (14 by 20 mm) galls to form on the stems of Cape-ivy. Female P. regalis oviposit 1-20 eggs into stem nodes or growing tips of Cape-ivy. During her lifetime, a female may oviposit up to 138 eggs (mean = 61.5 eggs). After 2 wk, the first swellings, indicating gall formation, become visible. There are three larval stages, and, 1 mo after oviposition, the gall is fully formed, and the larvae within scrape a small circular hole through the gall wall, leaving a "window" covered by intact plant cuticle. After another month, adult flies break the window and emerge from the gall. The life cycle from oviposition to adult emergence is approximately 2 mo, and we observed up to seven generations in a year in our quarantine laboratory. Females begin ovipositing within a day or two of emergence, and adults live for approximately 2 wk. We compare the life history of P. regalis to the published information about other Parafreutreta species.