A survey of fruit-feeding insects and their parasitoids occurring on wild olives, Olea europaea ssp. cuspidata, in the Eastern Cape of South Africa

Abstract

Fruits of wild olives, Olea europaea ssp. cuspidata (Wall. ex G. Don) Cif., were collected in the Eastern Cape, South Africa, during 2003–2005 to quantify levels of fruit-infesting pests and their parasitoids. Two species of Tephritidae, Bactrocera oleae (Rossi) and B. biguttula (Bezzi), were the most abundant insects recovered and were reared from most samples. Fruit infestation rates by the Bactrocera spp. were generally below 8% and over half of the infestations were under 1%. When parasitism occurred in samples with flies, levels ranged from 7 to 83%. Several species of opiine braconid wasps, Psyttalia concolor (Szépligeti), Psyttalia lounsburyi (Silvestri), and Utetes africanus (Szépligeti) and one braconine wasp, Bracon celer Szépligeti, were reared from fruits containing B. oleae and/or B. biguttula. Chalcidoid parasitoids and seed wasps included seven species of Eurytomidae (Eurytoma oleae, Eurytoma sp., and Sycophila sp.), Ormyridae (Ormyrus sp.), Torymidae (Megastigmus sp.), and Eupelmidae (Eupelmus afer and E. spermophilus). One species of moth, Palpita unionalis (Hübner) (Crambidae), was recovered in very low numbers and without parasitoids. The survey results indicate that fruit flies might not become economic pests of the nascent commercial olive industry in the Eastern Cape, and the small numbers present may be controlled to a considerable level by natural enemies.

Keywords:

• olives
• Bactrocera oleae
• Bactrocera biguttula
• fruit fly
• parasitoid
• Braconidae
• Psyttalia
• Bracon
• Utetes
• biological control

This work is declared a work of the United States Government and is not subject to copyright protection: approved for public release; distribution is unlimited

This work is declared a work of the United States Government and is not subject to copyright protection: approved for public release; distribution is unlimited

Acknowledgements

We thank the many Eastern Cape olive growers that were involved for allowing access to their farms; A. Stylianou (Chairman, Ncera Agricultural Development Corporation) for weather data; Alan Kirk, Charles Willemse, and Jabulani S. Mthombeni for helping with fruit collection and sample processing; Ian M. White (Department of Entomology, The Natural History Museum, London) for identifying fruit flies; Charles H. Pickett (California Department of Food and Agriculture-Biological Control Program) and Robert A. Wharton (Department of Entomology, Texas A&M University) for identifying parasitoids; Martin Krüger (Transvaal Museum, Pretoria) for identifying moths; Tony Dold (Selmar Schonland Herbarium, Rhodes University, Grahamstown) for identifying plants; Bronwyn McLean (Graphics Service Unit, Rhodes University) for graphics; and the US Department of Agriculture Agricultural–Research Service, South Africa's National Research Foundation, the Andrew Mellon Foundation and the Rhodes University Joint Research Council for financial support. Any opinion, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Research Foundation.

Notes

This work is declared a work of the United States Government and is not subject to copyright protection: approved for public release; distribution is unlimited

Additional information

Notes on contributors

Nolwazi Mkize

Current address: Nolwazi Mkize, Department of Agriculture – Food Safety and Quality Assurance Directorate, Pretoria, South Africa