20/12/2025
January is traditionally the peak of Mediterranean Fruit fly (or Medfly), activity in the region. Not to be confused with the Queensland Fruit fly outbreak last season, Medfly has been in WA since 1895. Whilst Busselton residents are all too familiar with these arthropods, their presence has largely been sporadic further south. However with increasing population and a climate tending warmer they’ve been showing up in more and more backyards. There are many fun facts about Medfly and plenty of elaboration to the topics below, but let’s keep it simple for facebook, and go straight to management: there are three organic options:
1. Bait
2. Lure and Trap
3. Exclusion
(Hopefully it’s needless to say that any fallen fruit should be disposed of. If it’s too numerous to pick up, running over the lot with a mower will do the trick.)
The first management option is baiting. There are a few large and expensive supplies but the only home gardener pack seems to be here:
https://www.yates.com.au/yates-200ml-natures-way-fruit-fly-control/
This is applied as droplets to the underside of leaves. 3-4 droplets per tree is sufficient The droplets should be large and need to stay fluid to be effective, thus it needs re-application weekly. It can also be applied to coloured plastic or cardboard and hung in the tree. Yellow or orange is colour of choice, and larger the better.
It can be awkward and wasteful to get a garden sprayer to apply droplets so it’s often easiest to flick the bait on with a paint brush.
Secondly, Lure and Trap. This is the more familiar solution to most, however I find it not as effective as bait. The trap and the lure liquid can be made at home, a google search will steer you there. If you’d rather buy something I’ve found Biotrap V2 with sticky traps to be the most successful, and they also make it easy to monitor Medfly activity:
https://www.pestrol.com.au/buy-online/biotrap-qld-female-fruit-fly-trap/?gad_source=1&gad_campaignid=17182589695&gclid=Cj0KCQiAjJTKBhCjARIsAIMC448z4TEcsZWVZKvHA5jU7q2oDLpWgeT_k33S6W4sDHQTUOT2M8EIwsgaAiOqEALw_wcB
(Most commercial products are targeted at the larger Queensland fruit fly market over east but will also work on female Medfly in the smaller western market – it is only the male attractant that varies, and unnecessary for Medfly control)
Thirdly exclusion nets are available either as individual fruit bags or tree nets. They are effective but in the case of bags fruit must not touch the sides as Medfly can sting through. As for tree nets, they need tying off around the trunk: any access allowed to soil with give the emerging larvae access to the fruit.
https://www.sagehort.com.au/horticultural-materials/insect-mesh/page/2
Summer is the peak for Medfly activity with ripe Stone fruit their preference and their means of proliferation. However, Medfly spend much of their non-reproductive time in Citrus, where they both roost in Summer and persist through Winter. So if you happen to have Citrus nearby it is often prudent to bait or trap there. Medfly will also attack some Citrus, and Apples and Pears are susceptible too.
Any questions fire away in the comments.