I've been struggling with vats of flying, stinking, green bottle flies since the day I got chickens. They swarm and annoy and worst of all they're G R O S S. Way worse than house flies. A house fly is like an annoying teenage girl who says "like" every second word. Bottle flies are like an ever growing gang of 15 year old boys with a pack mentality, screaming f*ck at the top of their lungs at 2 in the morning and peeing into mailboxes. In other words, WAY more annoying.
Plus of course, bottle flies are dirty (they breed on poop, then fly over to your cob of corn and walk all over it) and they have the potential to kill your livestock through flystrike.
For years I've made and used these DIY fly traps which actually work GREAT but are a bit gross.
I've decided that instead of trying to fight these flies with traps and sticky tape I'm going to just let nature take its course. If you can't beat 'em, join 'em. Live and let live and all that. In fact, as an apology for all the trapping and sticking I've tried to do, I even got the bottle flies some friends to play with! I ordered them special. Bug buddies!
The fly parasite is actually a parasitic wasp. I was so sure they'd get along with my bottle flies, but as it turns out ... fly parasites actually attack and kill bottle flies.
Who knew? I did. Because reader Shauna Henry told me so last year. She uses them in her chicken coop.
I ordered 10,000 of them.
You can get delivery of 10,000 parasitic flies for about $20. How they work is they attack bottle flies when they're in their pupa stage. The parasitic wasp burrows into the bottle fly pupa, kills it, then moves on. Over and over again. So the bottle flies are killed even before they become flies. So tragic.
Gosh. And I thought I was just inviting over a few friends for my bottle flies. Instead they were all killed in a homicidal frenzy. Such a shame.
Depending on how many flies you have, you need to get delivery of new fly parasites every 2-4 weeks through the summer.
There are a lot of companies online you can order them from. Here in Southern Ontario I got them from Bugs for Bugs, Natural Pest Management.
The fly parasites are gnat size parasitic wasps that are nocturnal and don't bother with humans at all. All they want to do is attack and kill fly pupa. They're good like that.
The fly parasites arrive at your house in a small bag, in small box a couple of days before they've hatched. You just sprinkle them around the bottle fly gangland and wait.
Because I have chickens who are notoriously curious and hungry (Norma the chicken once proved this when she lunged at me and ripped a half carat diamond earring out of my earlobe), I did my best to hide the fly parasites when I sprinkled them. I put them under the poop board and behind boxes in the run and anywhere I could find that they'd be protected until they emerged. Fly parasites are incredibly effective killing machines, but they can't do much of anything if they're in your chicken's gizzard.
I sprinkled them around the edge of the coop ...
... on their ladder steps ...
... under their poop board.
Just days after I added the fly parasites to my coop area it got REALLY hot here in Southern Ontario. Crazy hot. Idris Elba hot. Which happens to be the preferred weather condition of bottle flies. Normally when it heats up bottle flies seem to multiply within minutes, covering everything in sight with their bottle fly rave dance party. I hate them.
But this year when the weather heated up there wasn't a fly to be found. Well, there were a couple but not many.
Conclusion? Fly Parasites seem like something out of science fiction. And they are. And that's probably why they work. It's nature versus nature just like on an episode of Mutual of Omaha's Wild Kingdom. And like that tv show I gave nature a little bit of a hand, by bringing the fly parasites in myself. I basically let nature take it's course, I just made sure there was a fair fight.
I'm still going to make my old fashioned fly trap, because I still want to trap the few flies that escape the fly parasites. It's always good to use at least 2 methods when you want to protect yourself. Any well seasoned lady of the evening will tell you the same thing.
I'll keep getting delivery of these fly parasites every 3 weeks throughout the summer and that should keep the bottle fly population quieted down quite a bit. I'm encouraging my supplier to come up with a 15 year old boy parasite to quieten them down but so far no luck.
Like, I'm not even, like, sure a, like, 15 year old girl would, like, do the trick.
HELP! I just came across this article in 2024, and I can't find a reputable supplier. I can't find "Bugs for Bugs Natural Pest Management" on the web, except for one company in Australia by that name. I tried to use Karen's widget and buy some from Amazon so she'd get a little dough, but the comments about the company that sells wasps through Amazon are ... unkind. I found some other, unrated sellers, but they only sell in large quantities, esp. in subscriptions.
And suggestions?
P.S. to Karen, should she see this message: I never did get more than one or two of your wonderful newsletters. I re-upped, but still didn't get 'em. I did check my Spam folder, but your missives were never misdirected there.
Hi Scotty. Bugs for Bugs is in Canada. They're the only provider I've used and they were great. But if you're not in Canada I don't imagine that they can send bugs across borders. :) ~ karen!
Ah-HAH! I didn't know that I had to use a .ca suffix to get netsearch results, and that did the trick this time. The hotlink in your kind reply worked perfectly as well.
Search engines that work down here in God's Country didn't work so terrif in furnishing results for Bugs for Beds because it's in,uh, Canadia.
Anyways, I'm on the correct website as we speak, and I thank you yet again.
The parasitic wasps also work in a rabbitry!
I didn’t have a fly problem with just horses and chickens; but added rabbits and whoa!!
Tried the wasps two years ago and they were still working last summer; so I believe some must have bred successfully on my farm. Going to reorder soon to give them a hand!
Thanks for the article!
We have regular flies (not sure they're green bottle flies) on our farm. Pretty sure a lot of those flies are coming from the farm down the way. And the they come and multiple on our property. Do you think you method with the fly parasites would work? Just curious and also wondering if a green bottle fly is the same as a regular fly
Hi Amy. A green bottle fly isn't the same as a house fly. You can tell the difference because the bodies of bottle flies are iridescent green and they're bigger than regular flies. Those kind of flies breed around poop. The parasitic wasps will work with any flies but the trick is to place them where there's likely to be fly larvae. Around a farm that's anywhere near where the poop is. For you a better solution might be a fly trap like this. https://www.theartofdoingstuff.com/the-best-homemade-flytrap-and-it-probably-isnt-the-one-you-see-all-over-pinterest/ ~ karen!
I don't know how I missed this post. Must've been on vacation. Next summer, definitely. Thank you, Karen.
Karen - I shared a link to this post on a local Facebook page (Orangevale, CA) to help someone out with the pesky fly problem they have due to their neighbors chickens.
Thanks for sharing this tip. I hope it works as well for her as it did/does for you!
Interesting, I've never heard of fly parasites.
We have tons of flies in our coop, but I think they are just normal garbage flies (not that they are less gross....)
Karen,
I thought I wanted to have a few chickens, but your posts scare me.:)
Are they worth all of your efforts??
Well, that's part of the reason I do these posts Cheryl. :) So people can see what it's really like to own chickens. Not just the "Pinterest version" of owning chickens where they romp through pea gravel and look beautiful. For me, yes they're worth the effort. I love them. But they're a responsibility for sure. They're livestock that needs to be taken care of. Generally they're easy but issues do come up. But if you want the Pinterest version of chickens ... stick to Pinterest. :) ~ karen!
Penny - I understand your concern. Please don't worry - they are a sponsored colony, this is allowed in my county, and I am their registered caretaker - they are a TNR colony (trap, neuiter, release) shots, and microchipped. The hang out mostly in my fenced back yard. I got involved in TNR because the cats WERE breeding around here like crazy, and I wanted to do something about it. population has dropped by more than half, and there are NO wandering male cats anymore. So, I am doing a good thing..... I just wondered about using the pwasp for keeping flies out of the food station.
This sounds great. I feed a small feral cat colony, and I no sooner put their dry food out, in the morning and the flies are all over. Starts again, (if they even leave) when I feed wet food early evening. Would I just sprinkle them in the same area? There is no poop around for them to lay eggs on.
Why (and where) in the world are you feeding feral cats?? Unless they're all neutered you should know that they WILL breed to take care of all the available food in their territory; including nesting and fledgling birds and small rodents such as voles.
You had me with that first paragraph. Such lovely descriptive writing.
Does your mother know you're using those words?
Ha. Betty taught you how to spell them, didn't she?
Fun blog. Just what I needed today, as it happens!
And just by mentioning Norma watching a diamond you're suddenly in the same category as 2 other certain very famous blondes, Marie Antoinette as a faux pheasant at the Petit Trianon and Catherine Deneuve talking about her chickens during a fitting at Yves Saint Laurent at the beginning of a documentary about Yves. How in heavens name do you manage such things while talking about poop?!!!!
Hey Karen - I used to get updates and then for some reason stopped getting them and so I signed up again, and I've done it a couple of times, but I don't get signed up.
Hi Cynthia! Hmm. Well I've just checked and you've successfully signed up this time. Keep an eye on it. You should get an email for my next post Friday! From the look of it you hadn't successfully signed up before (at least not with this email address). Fingers crossed! ~karen!
Don't even need to read the post - just need to tell you that these things work. We've used them since we've had chickens and they work great. Now, I'll go read the post because you may already know that they work:)
OMG OMG, you mentioned me! hee hee:)
LOL! ~ k!
I use a different kind of parasitic wasp (trichogramma I think) through the summer to keep down the wool moth population in my house. Love letting nature do the work. I'm still looking for that backup solution though....any ideas?
What is a poop board (sounds technical)?
Hi Jan! A poop board is just a board that goes under where the chickens roost at night. It makes it easy to clean out their coop because you just pick up the board and scrape it all into the compost bin. :) ~ karen!
OH! Cool/yuck
Can I just say I love your writing. You tie things together so well, Glad the flies are out of there.
Hey Karen
What's the purpose of a poop board?
Hey Snugster! The poop board goes under the roost where the hens sleep at night so when they poop it lands on the board. It makes cleaning the coop easy because you just have to pick up the board and scrape it into the compost bin every couple of days. ~ karen!
I wonder if they sell ladybugs? I need to order some for my garden.
Who knew??? Your blog is the best thing ever! You make us laugh, you make us cry and you find the most interesting facts to educate us! Don't ever stop writing!
Don't worry, I won't. Not in the immediate future anyway. ;) ~ karen!
More power to you! I wish I had something for the deer flies that were flying around and around and around and around my head yesterday as I was painting the shed. I tried ignoring them (fail), waving my hands over my head like an idiot (fail - the waving hands part, not the idiot part), spraying them with water (fail). I think they're even more annoying than blackflies. Why do these bothersome things even exist???
Try Picardarin.