Pest-risk analysis of fruit fly introductions and assessment of current fruit fly management practices

A study was conducted on adult fruit fly population and fruit infestation in five areas of the Western Cape from May 2006 to April 2008. The objectives of the study were to: (1) monitor for presence of foreign fruit fly species and (2) assess the relative success of current fruit fly management practices- Bait Application Technique and Sterile Insect Technique. With respect to foreign fruit fly species, more precisely the most aggressive one on the African continent to date- Bactrocera invadens, the potential of establishment in South Africa was determined using a climatic model (CLIMEX).

To date, no foreign fruit fly species have been detected in Western Cape. Results from the climate model indicated that there is a potential of establishment of this fly in various parts of South Africa, in particular in the north eastern areas, along the east coast and coastal areas of the Eastern and Western Cape. However, these results should not be interpreted as definitive since data used in this model was limited.

There were no distinct differences in fruit fly population levels and fruit infestation between areas under Bait Application Technique and Sterile Insect Technique. The efficacy of Sterile Insect Technique was low in areas which were under a high fruit fly population pressure. The importance of integrating other fruit fly control tools such as baiting and orchard sanitation in areas that are under Sterile Insect Technique was discussed.