The Mediterranean olive industry experiences significant losses due to the olive fruit fly (Bactrocera oleae: Diptera: Tephritidae), which negatively affects the production of table olives, as well as olive oil. In the Western Cape, however, economic losses due to severe infestations of olive fruit fly only occur intermittently. The number of fruit flies from year to year is probably correlated with climate fluxes which affect not only the pest, but also its natural enemies, the wasps, beetles, and bugs which normally prey on the fruit fly or parasitise to keep its numbers naturally low. But, as the climate becomes ever more unpredictable and the South African olive industry grows, there exists a real threat of olive fruit fly becoming a more significant pest.
Monitoring pest populations of olive fruit fly is the first step in developing a management strategy for control. In order to create a monitoring system with measurable action thresholds in South Africa, where none exists for olive fruit fly, determining the best monitoring method is key. Researchers in the Department of Conservation Ecology and Entomology, Francois Bekker, Pia Addison and Matthew Addison, have conducted a study to compare the efficacy of two commercially available traps for the capture of olive fruit fly, delta traps and bucket traps, both loaded with a mixture of chemicals known to attract male and female olive fruit flies.
South African olive farmers currently use delta traps for monitoring olive fruit flies, but its efficacy has not yet been assessed. Mediterranean olive farmers, on the other hand, have used bucket traps for decades. The trial was conducted in 20 commercial olive groves in the Western Cape. Results showed that the trap currently in use, the delta trap, performed better than the bucket trap. The overall conclusion was that the trapping system currently in use by Western Cape olive farmers was satisfactory. This finding now allows for further research to investigate economic thresholds and management practices for control of olive fruit fly in the Western Cape.
– Stellenbosch University AgriSciences