Gardening tips, gardening info and heaps of ideas to help gardeners of all experience get more out of their hobby and out of their gardens.
We scored a whole bag of mandarins from some friends last weekend, only to find that they were riddled with fruit flies - well, baby maggots to be precise. My daughter had picked them directly from the tree and there was not even a hint of disturbance to these gorgeous citrus. To the untrained eye, they even looked better than the shop-bought varieties.
Peel away the skin and the flesh began moving more than the ceiling after a hard night. Fly larvae - maggots - were wriggling through the fruit intent on devouring as much as they could. Instantly the adage "Don't judge a book by it's cover" flooded my memory as I disappointedly began checking the rest.
One or two were free of the infestation but the majority were write-offs. Given another week or two these fruit would begin rotting on the tree providing a glorious dwelling and upbringing for the next generation of these pests.
I should have taken the cue "We didn't get the tree sprayed this year!" as a major hint that fruit flies may have been a problem in the area. Instead I thought, "Great, these people grow their fruit organically". Doh, Doh!
How can you stop flies from infesting your fruit?
Prevention is obviously the first place to start. Traditionally most people have used chemical sprays once the fruit has set and before it begins to mature. Fruit bought from retail outlets usually undergoes two sprays - pre-harvest and post-harvest. The post-harvest pesticide is to combat infestations that may occur while in transit and before the consumer eventually eats it.
While most pesticides used to treat fruit fly are fairly sedate they work by inhibiting cholinesterase - an enzyme required by the animal kingdom for proper nerve functioning. While these inhibitors work wonders on fruit fly in minute amounts if the dosage were increased it could cause nausea, stomach cramps, blurred vision and even an increase in your heart rate. Hardly something you might consider as you begin munching into your mandarin.
While spraying may be the easiest method of fly control the side effects and health concerns for parents are obvious. Therefore, organic eradication is slightly more attractive.
The best way to start is with a trap of some description. Some use jars suspended from the fruit tree while others have more elaborate traps (aff.) set to catch thousands of unwanted flies.
The trick with making these work is as follows;
These are the basics of any organic fruit fly control. It's quite simple in its manufacture and easy to maintain though you can see why some people prefer pesticides as the set-and-forget method.
What to do with fly-ridden fruit?
Definitely don't throw it in the garbage or on the compost heap. These are both perfect breeding conditions for fruit fly and instead they should be destroyed.
One method offered by various government websites is to soak them in kerosene. The problem with that is kerosene is hardly an organic resource. So I tried two different methods with our spoilt fruit. The first was in a bucket of water and while the fruit had to be kept from floating it did eventually do the job - it took two days though.
The second method was using oil - the plain old cooking variety. The maggots were dead within 12 hours (it may have been sooner but I didn't check them for half a day). The obvious problem with this method was what to do with the fruit once the maggots had been killed. The only option was to put them in the garbage while the fruit covered with water could then either be put in a hole in the garden or added to your compost.
Comments
great info.
Posted by: deb | July 10, 2008 1:29 PM
Thanks Deb.
Posted by: Stuart | July 10, 2008 3:03 PM
A trick that always works well for me -- place a small amount of apple cider vinegar in a shallow bowl; cover tightly with a plastic cling wrap; poke several holes in the taut plastic with toothpicks, small skewer, etc. The pesky flies will crawl in, but not be able to crawl back out. Some fall into the vinegar and drown, and some just expire, period. The flies start to hover around while you're filling the dish. It never fails. Until the next crop. :)
Posted by: Nancy Bond | July 11, 2008 4:19 AM
Oh, this happened to me! Except I tried bleach and it took a whole day to kill them. Thanks for the tips I surely will use the suggestions for catching the fruit flies.
Posted by: Sabrina | July 26, 2008 1:29 PM
Glad I found your blog on someone elses. For the first time in 55yrs of gardening in Oz-land had fruit fly in my tomatos last summer. The traps are a great idea. We're clean and green, anything with numbers, colours or flavouring goes back on the supermarket shelf. You may like to check out my daughter India Flint's latest book on ECO COLOUR, especially on man-made dyes and fabrics if you have children. Thanks again.
Posted by: Anonymous | July 31, 2008 11:54 PM