Development of female fruit fly, Ceratitis species, attractant systems for trapping and sterility assessment in South Africa

Fruit in the Western Cape Province of South Africa is attacked by the Mediterranean fruit fly, Ceratitis capitata, and the Natal fruit fly, C. rosa. Control costs and crop losses amount to an estimated US$ 5 million per year. The ARC-Fruit, Vine and Wine Research Institute in Stellenbosch has been taking part in the FAO/IAEA Co-ordinated Research Programme (CRP) to develop a female attractant systems for C. capitata during the 1996/97 and 1997/98 growing seasons. These seasons represented Year 3 and Year 4, respectively, of the female attractant CRP. The performance of these attractant systems in monitoring C. rosa was also evaluated. The Year 3 trial was carried out in a plum orchard with a low fruit fly population, and the Year 4 trial was carried out in the same plum orchard, as well as in a pear orchard with a high fruit fly population. Four female trapping systems were evaluated in Year 3 and five in Year 4. In Year 3, two systems consisted of a locally-manufactured buckettype 'Sensus' trap containing one of two different female attractants (β-caryophyllene, or β-caryophyllene + protein hydrolysate), one was a McPhail trap (IPMT) baited with borax + protein hydrolysate, and the fourth was an open bottom dry trap (OBDT) baited with the three component ammonium acetate, putrescine and trimethylamine system (FA-3). Sensus traps and Jackson traps baited with the male fruit fly attractant Trimedlure (TML) were also included. In Year 4, there was one wet and one dry IPMT system (both baited with FA-3), one IPMT system (borax + protein hydrolysate), and one wet and one dry Tephri trap system (both with FA-3). Jackson traps baited with TML were also included. Results from Year 3 showed that of the systems tested, the best female C. capitata attractant systems under low population conditions were the IPMT system baited with borax + protein hydrolysate, and the OBDT system baited with FA-3. β-caryophyllene in a Sensus trap did not adequately attract female C. capitata. No conclusions could be drawn on C. rosa in this trial. In Year 4, the most effective traps for both C capitata and C rosa females were the wet TEPHRI (FA-3) and the wet IPMT (FA-3) systems. The least effective systems for females of both species were the dry TEPHRI (FA-3) system and the IPMT (borax + protein hydrolysate) system. Fruit fly population levels affected the performance of some systems. (author)