Mosquito Dunk Fruit Fly Fungus Gnat Update

Fruit fly larvae – up close and personal
Back in the middle of August (oh how time flies!) I wrote a post about my plans to test out ‘Mosquito Dunks’ as a means of getting rid of fruit flies and fungus gnats in a worm bin (see “Can Mosquito Dunks Kill Fungus Gnats and Fruit Flies?“). Well of course – me being me – while I DID get around to setting up some bins outside to attract some fruit flies, I failed to actually get going with the experiment until some really cold fall weather finally made me realize I needed to act fast or risk losing my outdoor fruit fly ‘culture’.
So, being the smart fellow that I am, I decided to bring a culture of fruit flies indoors where my systems were happily chugging along, fruit-fly-free! Oh well – I always enjoy ‘taking one for the team’ in order to make a learning experience out of it, so now that I am enjoying a serious infestation of fruit flies in my basement, I know it’s finally time to get started!
I’ve set up a bunch of new apple cider traps, and the other day I started brewing my mosquito dunk water. I’ve decided to proceed somewhat cautiously with this experiment – largely due to the fact that someone left a comment on the other post (mentioned above), indicating the potential for actually harming the worms. While I’m not 100% convinced that this will be the case, I also don’t feel like being so reckless with my worms’ well-being as to simply starting pouring the stuff on my indoor beds. I might as well make sure it’s even going to kill the larvae before taking the risk of inflicting harm on my dear wormies!
As such, the original fruit fly culture container brought in from outside has become ‘ground zero’ for my experimentation.

This container has a piece of corrugated cardboard and a virtually-liquefied cucumber in it. There are lots of fruit fly larvae visible on the cardboard (such as those ones in the first pic) and until recently there were also lots of adults. I released them all when I opened the system to apply the dunk liquid A) accidentally and B) because I am trying to see if the larvae will mature into adults once their food source has been soaked in ‘dunk juice’ (Brain wave! If all this works out for me – I should really think about marketing my new fruit fly killer as ‘Dipteran Dunk Juice’! Haha).
To apply the liquid I used a small syringe and slowly soaked all zones where the larvae were visible – I made sure to move any run-off around the entire container as well.
So far so good – all I noticed today was the presence of two tiny adults. Fruit flies develop VERY quickly, so I’m hopeful that this is a positive sign. Many of the larvae DO still seem to be moving around, but we’ll see how they are doing in another day or two. The bacterium in ‘Dipteran Dunk Juice’ (TM) causes these larvae to stop feeding – so it’s not like some sort of instant poison or anything like that.
If it looks like the larvae are dying off, and no more adults are being produced we’ll move on to ‘phase II’. I’m still not planning to put the liquid on my actual beds yet – first I will set up a small experimental system, perhaps with a chunk of rotten fruit (or fruit-juice-soaked cardboard) in it, along with some worm bin material and a small number of worms.
Stayed tuned!
Written by Bentley on November 5th, 2009 with
9 comments.
Read more articles on Home Vermicomposting and Worm Bin Creatures.


282 lb of Food Waste, and Counting!
#1. November 5th, 2009, at 10:49 PM.
Bentley,
Great website!!! I’m a vermicomposting newbie; I started with 150 worms in April 2009, and now I have a thriving herd thanks to what I’ve learned here at RWC!! I’ve read every article that you have posted, but I must say I’m REALLY looking forward to your updates on the mosquito dunk experiment. Fruit flies have taken up residence in my basement and my wife will throw a fit (along with my worm bins) if she ever finds out about it (luckily she doesn’t venture into the basement too often).