Controlling Mediterranean fruit fly: bait spraying

Page last updated: Thursday, 30 August 2018 - 10:59am

Please note: This content may be out of date and is currently under review.

Common problems

If Medfly numbers continue to increase, application may be incorrect.

If this occurs, check the following:

  • Are you using the correct formulation? Check against Tables 1 and 3.
  • How old is the insecticide and protein? Potency or attraction can decrease with time.
  • Have you been mixing new batches of bait each time that you use it? The potency of the bait mixture decreases and all bait should be used on the same day that it is mixed.
  • What is the pH of your water? High pH can degrade some insecticide formulations rapidly. A pH range between 5.6 and 6.5 is preferred.
  • Is the nozzle wide enough to deliver a coarse spray? When sprayed, the bait should form large droplets on the foliage of the tree. If droplets are too fine, they will dry out rapidly and loose potency.
  • Is enough bait being applied? Are you applying bait frequently enough? Calibrate your equipment to ensure you are putting out what you think you are.
  • Has it been a particularly wet season? Rain washes off the bait and it should be re-applied after rain.
  • Has orchard hygiene been maintained? If not, Medfly will continue to emerge from infested fruit and re-invade treated areas.


Commercial and industry enquiries should be directed to Medfly Compliance, all public enquiries should be directed to PaDIS.

Contact information

Pest and Disease Information Service (PaDIS)
+61 (0)8 9368 3080
Commercial Medfly Enquiries Only