Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2009
Publication Date: February 1, 2010
Citation: Balciunas, J.K., Mehelis, C.N. 2010. Life history of Parafreutreta regalis, (diptera:tephritidae), a candidate agent for biological control of delairea odorata. Environmental Entomology. 39(1):114-120. Interpretive Summary: Invasive weeds degrade natural areas, cause billions dollars worth of losses in agriculture, and weed control accounts for more than half the pesticides used in the United States. Classical biological control – the release of carefully selected and tested insects and other natural enemies from the native home of the weed – is a proven strategy for reducing the impacts of invasive weeds, and reducing the use of herbicides. To avoid direct impacts on crops and beneficial native plants, prior to release, the intended agents are screened to assure that they are host-specific, and will not damage non-targets. This paper presents the life history of a gall fly being considered for use as biological control agent for Cape-ivy. This information has been useful in determining the host specificity of this fly, and will help optimize strategies for releasing it, if permission is obtained. If permission for release is granted, this fly could prove to be a valuable management tool for controlling Cape-ivy.
Technical Abstract: 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 x 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. After 2 wk, the first swellings, indicating gall formation, become visible. A month 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 two months, and we have 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.