Steinernema feltiae VS The Fruit Flies

As mentioned in my recent post about gnat-killing-nematodes, I’ve decided to test out these nematodes against another pesky worm bin fly – the fruit fly! They are reported to be effective against a wide assortment of fly (and other insect) larvae, and as I’ve discovered they do actually work reasonably well against fungus gnats.

I must admit to having zero trouble breeding my initial stock of fruit flies. One of the waste materials I receive from my restaurant composting project is apple waste – lots and lots of it, I might add. It consists of cores and heaps of long apple peelings that have been removed with a special machine, so everything is very uniform. The peels strings are a little creepy actually, resembling squid tentacles, or a heap of…gasp…WORMS!!

Anyway – this stuff is prime fodder for fruit flies, as I have discovered in my outdoor composting systems! All I did to attract my initial bunch of breeding adults was put some of this material in a small, lidless rubbermaid bin (outside) and let it sit. It didn’t take long before swarms of fruit flies were hovering around the bin.

I next divided the peelings between two separate bins, added lids, then simply left them to sit in a larger bin for a number of days – plenty of time for the fruit flies to do their business and for larvae to start hatching.

Today, I drained off the liquid from the decaying apple sludge (which contains zillions of little fruit fly maggots), added some absorbent cardboard so that it’s not quite so much of a sloppy mess, then added some of my trusty nematodes to one of the bins

As per usual, this is not meant to be a rigorous scientific experiment by any means. I simply want to see what happens. Hopefully the nematodes will have a pretty major impact on the fruit fly larvae in the one bin, but we shall see. The nematodes are only supposed to be good for a couple weeks in the fridge, and I think I’ve past that point now, so they very well may be no good anyway.

Only one way to find out!

I’ll be sure to keep everyone posted!

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    • Asha
    • July 18, 2008

    I have been lurking on your site for sometime now. Very interesting to read your experiments with the worms. Waiting to see what happens with this one! Never thought fruit flies could be a good thing after all 🙂

    • Dwayne
    • July 18, 2008


    I used nematodes on soldier fly maggots. It worked for a while and now they are back. I think I have read that you must re-treat ever so often. I have gotten used to them but it did seem to work and should work on the fruit flies.


    • Bentley
    • July 19, 2008

    Thanks for popping by Asha – I’m certainly looking forward to the results myself. Hopefully I’ll end up with a bin full of nematodes (and dead fruit fly larvae), so I can add them elsewhere.

    Dwayne – I suspect you are right. Part of the reason I am testing them out like this is to see if I can create something of an ongoing culture of the nematodes. It will obviously be a little more difficult in the winter (don’t want to keep lots of fruit flies inside), but I’m going to research the biology of these nematodes a little more and see if there is some way to make them go dormant without killing them. They aren’t super cheap (or readily available) so I’d prefer it if I didn’t have to order more.

    • January 15, 2015

    I was raising praying mantids in my house and had to keep fruit flies (wingless) in jars to feed the babies.
    So my opinion, if you want the flies gone, raise praying mantids.
    You can buy the eggs on ebay and hatch out about 300 babies per egg.
    Of course when the mantids got bigger, I had to raise silkworms as there were not enough bugs to be found for them to eat.

    • Breegine French
    • August 1, 2015

    I’ve been at the end of my teather with fruit flies in compost bin and kitchen for the past week even though never had problem before. Just had a brainwave and sprinkled a kettle full of boiling water over open bin. BINGO instant solution! Maybe not the kindest or eco friendly approach but a relief for now.

    • Breegine French
    • August 1, 2015

    Just realised Im in wrong section for last comment mine is regular composer not a wormer

    • Bentley
    • August 7, 2015

    Breegine – glad you sent the follow-up comment! I was pretty worried! lol

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