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– How SIT can help producers
– The future of fruit fly SIT

How Sterile Insect Technique can help producers

Experience in other countries has shown that three objectives are possible with Sterile Insect Technique, with increasing cost implications but with increasing benefits:

  • Fruit fly control or suppression in a cost-effective, environmentally compatible manner.
  • Creation of an area of low fruit fly prevalence. Fruit flies are present, but at extremely low levels (e.g. an average of 0.001 to 0.0001 flies/trap/day), which may be acceptable to many discriminatory countries.
  • Creation of a fruit fly-free area (= eradication; 0 flies/trap/day over at least 12 months), with a fruit fly-free certificate. This will entail establishing quarantine zones to prevent fertile fruit flies being brought into the area by human movement, and is an operation managed and financed by government. There is increasing international awareness that it is very difficult and costly to achieve and maintain a fruit fly-free area.

At present the fruit fly sterile insect technique can only be used for Medflies.

The future of fruit fly Sterile Insect Technique

The aim of the Hex Valley Project was to achieve economical control of fruit flies using an ecologically compatible method. This was largely been achieved. Other fruit production areas have since been included in the SIT programme, viz. the Elgin/Grabouw/Vyeboom and Villiersdorp (EGVV) areas, the Warm Bokkeveld, Wolseley and Tulbagh.

In these areas, approximately 14,000 ha of commercial fruit are being protected by ground releases of sterile male Medflies in strategic localities.

However, the fruit fly suppression programme must be taken to its logical conclusion – eradication. This exercise is very costly, and arguably impossible, when attempted over a relatively small area, as it requires effective quarantine measures to be implemented in the area. Eradication will only become cost-effective when additional fruit production regions are included under the SIT “blanket”. The SIT programme is scheduled to be extended by 2015 to additional fruit production areas in the country, so that about 70% of all plantings will be included.

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