A survey of Ceratitis quinaria (Bezzi) (Diptera: Tephritidae) in citrus production areas in South Africa

The five-spotted fruit fly, Ceratitis quinaria (Bezzi) (Diptera: Tephritidae), is distributed in parts of eastern and western Africa, northern Africa and southern Africa (including South Africa). The species also occurs outside of Africa, in Yemen. The host range of C. quinaria is narrow, with Mangifera indica L. being the main host of commercial importance. Ceratitis quinaria was claimed to be associated with citrus in Sudan although this claim was never substantiated and there has never been any confirmed reared record of C. quinaria on citrus despite numerous surveys of citrus across Africa. In order to verify the type of association that C. quinaria has with citrus, field surveys were carried out in South Africa to determine the distribution and seasonal occurrence of C. quinaria in commercial citrus orchards and the possible natural infestation of citrus by this species. Surveys on distribution of C. quinaria across South Africa were carried out in 1999 and 2000 by trapping with Ceratitislure (containing protein hydrolysate and beta-caryophyllene). The seasonal occurrence of C. quinaria in the northern areas of South Africa was determined over two years between 2015 and 2017 by trapping with Enriched Ginger Oil (EGO), a male lure containing alpha-copaene. In the same trapping period, citrus and other fruit were sampled to determine infestation by C. quinaria. Additionally between 2009 and 2018, citrus fruit was sampled from the trees and ground in other commercial and non-commercial areas in the north of South Africa. All fruit samples collected were incubated for at least five weeks to allow rearing of flies to the pupal and adult stages. Trapping surveys conducted between 1999 and 2000 showed the presence of C. quinaria only in the northern areas of South Africa. Catches of C. quinaria males in EGO-baited traps were low in commercial citrus orchards (peak of catches being lower than 0.05 flies/trap/day). Catches of C. quinaria were mainly recorded outside of the citrus ripening period. No C. quinaria was reared from any of the citrus fruit sampled, even in those areas where the presence of the species was demonstrated by catches in EGO-baited traps. The fruit surveys therefore demonstrated the absence of natural infestation of citrus with C. quinaria in South Africa and supported existing biological information that citrus is not a host for C. quinaria.