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The discovery of the exotic fruit fly pest Bactrocera dorsalis (Diptera: Tephritidae), previously recognized as Bactrocera invadens, on the African continent in 2003 raised biosecurity concerns in South Africa where agriculture is of major socio-economic importance. This prompted the development of a nationally coordinated system to prevent introduction of this pest into the country. A steering committee was constituted to provide a platform for multi-stakeholder cooperation. A national action plan on B. dorsalis was developed. A surveillance network was initiated to provide for early detection of B. dorsalis. The first B. dorsalis eradication campaign was launched in 2010 following the detection of the pest in the northern border region of South Africa. Multiple point incursions were detected thereafter in the northern parts of the country and for the first 2 years all of these were considered successfully eradicated. However, the rate and geographic spread of incursions increased over time. In March 2013 the pest was declared present in the Vhembe district, Limpopo Province. All areas affected by B. dorsalis were placed under quarantine and eradication actions are still ongoing in areas other than the Vhembe district. The national control strategy on B. dorsalis continues to be focussed on preventing further incursions, slowing the spread of the pest and monitoring the extent of its distribution within South Africa.

The influence of food sources comprising the natural diet on the reproductive behaviour, fecundity and longevity of three African fruit flies Ceratitis cosyra (Walker), C. fasciventris (Bezzi) and C. capitata (Wiedemann) was investigated. Three natural food sources, varying in protein and sugar content, were evaluated. These included bird droppings (farm chicken), aphid honeydew and guava (Psidium guajava L.) juice. For C. fasciventris and C. capitata, flies fed on a protein-rich diet displayed higher frequency of calling, mating and oviposition than flies fed on a protein-poor diet, whilst for C. cosyra, quality of diet significantly influenced the mating behaviour of the flies, but not the calling and oviposition behaviour. Net fecundity rates were lowest for C. fasciventris and C. capitata when fed only on guava juice (0.1, 2.6 eggs per female, respectively), and higher for those on a diet of honeydew only (9.5, 33.8 eggs per female, respectively) and a combined diet of guava, honeydew and chicken faeces (11.8, 25.8 eggs per female, respectively). For C. cosyra, due to low numbers of eggs collected, no significant differences in fecundity between diets could be detected. All species fed only on a diet of chicken faeces since emergence died within the first three days of adult life without laying eggs, but when carbohydrates were provided by addition of guava juice and honeydew, the longevity of the flies was sustained for more than four weeks after adult emergence. The practical implications of these findings for control purposes are discussed.

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