Mediterranean fruit fly is a major problem in our area. The Department of Agriculture (DAFWA) says that without control, it would infest 100% of stone fruit.
In summary, we need to apply a small amount of an attractant mixed with an insecticide every week. As a service to the community, the Progress Association has purchased a 25 kg container of Flavex, one of the recommended attractants and it is available to all local residents. Flavex will be available at the hall on the first and third Saturdays each month between 0930 and 1130 commencing on 7th November or phone 0407 175 564. Just bring a container and pick up 200 ml of this liquid (enough to make 20 litres of spray which would treat 10 fruit trees for the whole season). This is free for members of LCHPSA; non-members will be charged $2.
You will also need Maldison or Malathion (same thing) from a hardware or garden store. Instructions on mixing this and Falvex will also be provided. Baiting like this is only part of the solution. It is also advisable to cover spray with a recommended insecticide and hang lures in the trees. Lures are available from hardware and garden stores. Traps made of plastic bottles etc are not recommended as they do not catch a high proportion of the flies.
There is more detail at http://agspsrv34.agric.wa.gov.au/Ento/medfly.htm