Learn how to DIY a fly trap that actually works using a mason jar (a soda bottle works too) and bait. These results are 100% real from my own backyard using household items and a stinky bait.
This fly trap DIY works so well outside for green bottle flies, aka blowflies, that it'll turn your stomach. How's that for an endorsement? But more than the trap, the most important thing about this DIY - is the fly trap bait.
Living in an almost 200 year old house with backyard chickens means I've learned how to control a lot of pests.
The best time to control pests is BEFORE you see pests. And I know my flies. I dried and counted hundreds of fruit flies while coming up with the best possible fruit fly traps.
Catching flies is a whole lot easier if you start baiting before they start mating.
Get your fly trap made and placed outside a couple of days before warm weather arrives to keep the population under control from day 1.
As with most pest solutions, double whammying is the best way to go. Don't use just one method. Use several. For instance, pair these fly traps with controlling flies with natural predators like parasitic wasps.
When one of my chickens became sick with flystrike, a deadly affliction caused by bottle flies, I knew I had to head into battle against them.
I made and compared a few homemade fly traps including:
- a mason jar with paper cone
- a soda bottle with the top cut off and inverted
- good old fashioned fly strips (not DIY but I had to test them out!)
The results showed the trap wasn't so much the determining factor in how well a homemade trap worked - it was the bait.
Table of Contents
Mason Jar & Paper Cone Trap
Baited with raw shrimp.
SUPPLIES
- Mason jar
- Standard sized sheet of construction paper
- 1 raw shrimp
- water
INSTRUCTIONS
- Roll a piece of paper or cardstock into a cone and tape it together.
- Put the cone into a mason jar of any size, making sure there's room at the bottom of the jar for at least 2" of water. You may need to adjust the shape of your cone.
- Add water and a single raw shrimp to the jar.
- Wait. Within a couple of days your jar will be FULL of flies.
Yep. A raw shrimp allowed to rot in the sun for days until it has the putrid smell of liquid internal organs. That was the key to a successful fly trap.
Soda Pop Bottle Fly Trap
Baited with commercial, store bought fly bait (although not THIS fly bait which actually looks kind of great. I just ordered some.)
This is the basic DIY fly catcher you see all over Pinterest.
SUPPLIES
- Plastic soda bottle
- Scissors
- Commercial fly bait
INSTRUCTIONS
- Cut the top off of the plastic pop or water bottle.
- Flip the top upside down (it'll look like a funnel) and stick it back into the bottle.
- Pour a couple of inches of water into the bottom of the trap and then bait it.
In this experiment I used I used store bought fly bait. The container is a 2 litre pop bottle. The flies can get into the bottle, but can't figure out how to get out. Then they drown.
This trap caught NO flies. Not a single one.
But it isn't the design of the trap that was flawed, it was the bait. Store bought fly bait attracted no flies at all.
Fly bait is the most important part of your fly traps.
Fly Strips
The fly strip cost a couple of dollars and dangled sadly from my window frame enticing no flies at all, just hanging there like a limp tongue.
I wanted to make sure I gave all the fly traps a good shot so I kept them all out for a week. This is how things had progressed after 4 days.
Fly Trap Results
Mason Jar with natural fly bait (shrimp) - Caught HUNDREDS of flies in 4 days
Soda bottle with commercial fly bait - Caught ZERO flies in 4 days
Fly strip - Caught 7 flies in 4 days
After 4 days it was pretty clear that the rotting shrimp was the only way to go in terms of bait.
My homemade fly trap recommendations
The trap
Either the mason jar or soda bottle method will work very well to catch flies outdoors.
The bait
Raw shrimp is your BEST choice for fly trap bait.
For this experiment I only baited the soda bottle with commercial bait (which caught nothing) but since then I've tried it successfully with shrimp as a bait. It works just as well as the mason jar with paper cone.
Testing Different Baits
I experimented with different baits including:
- Fermented chicken feed
- Raw sweet corn
- Fresh chicken poop*
- Raw shrimp*
* If you use meat, seafood or poop understand that this gives the flies a place to lay their eggs. That means if you use any of these things that after several days you will ALSO have maggots appear in your fly trap. Consider this when choosing your bait.
The rotting shrimp was the winner by a shrimpboat load.
The only issue with the enticing smell of rotting shrimp was the vile smell of rotting shrimp. If you place your container up high enough (above nose level) you miss most of the stench but given any kind of downward breeze you suddenly feel like you're walking through a rotting whale carcass.
By day 7 I was pretty sure I would have to try something else because I couldn't stand the stench of the shrimp no matter how well it worked. Then a funny thing happened. By days 8 and 9 the trap was so filled with flies they actually suffocated the smell of the shrimp. Yet somehow the stink was enough to continue to attract the flies.
By day 14 the mason jar trap was almost completely FULL of flies.
Home Fly Trap on Day 14
Because there were so many flies I couldn't smell the shrimp at all and the jar was almost full.
After 20 days it stunk again. Stunk like the guts of a hot monkey. But the stink could have been the mass grave of flies as well.
To save myself some grief and whatever happens to be in my stomach, when it comes time to remove the jar I just tie a plastic bag around my head, put a lid on the jar and throw the whole thing in the garbage.
Just kidding. I don't tie a bag on my head. I'm an excellent breath holder on account of my cat's horrific gut issues when she - coincidentally - eats seafood.
Fly trap placement
The best place to put fly traps is actually AWAY from where your fly problem is. (The dog run/chicken coop/picnic area.) The point is to draw the flies way from wherever it is they're fond of.
Top Tip
To repeat ... the best way to get rid of flies around your house is to use TWO methods.
- Parasitic wasps (really just tiny little flying things that are in no way as menacing as their name alludes to) will kill most flies before they even become flies. The wasps kill them in the larvae stage.
AND
- A DIY fly trap like this (or you can buy a similar sort of trap)
What about indoor flies?
Honestly, I just horsetail them with a kitchen towel.
But you can try this indoor fly bait recipe if you want.
Fly Bait Recipe
- ½ cup water
- ½ cup vinegar
- 2 Tbsps sugar
- 1 tablespoon dish soap (the dish soap breaks the surface tension of the water and vinegar, making the flies unable to use it as a launching pad when they fall in it)
Use either the mason jar or plastic bottle method. You can use a small water bottle instead of a large soda bottle.
Now that you've mostly eliminated one insect from your yard (totally understandable, flies are sex crazed monsters that feed on crap and then land on your corn on the cob), you might want to help out another.
Learn how to raise monarch butterflies on you property, something I've been doing for over a decade.
If you have a great fly bait recipe, leave it in the comments below. If you have a great maggot story maybe just keep that to yourself. Just kidding. Obviously, I'd love to hear the maggot stories.
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Paulette M Clark
From our experience this weekend, dry fish flavored cat food would work too. It could be the tropical storm we are having right now but I was horrified when I went outside to check on stray cats and their food. The bowl was covered in flies! I mean a million of them. We've always had a few but this weekend they all came to dinner. And of course, they all tried to follow me into the house. My husband on a mission to eliminate all the flies so of course, he was out on the front porch with a fly swatter in the middle of a tropical storm, killing flies. And scaring the stray cats. So now I have to take the food as soon as they eat. I'm going to make a fly trap!
Susan
Haha the smell of rotting shrimp is a small comparison to the smell of rotting lobster. With lobster prices so low, it's tempting to eat more here in PEI but now my consumption has to be rationed according to the room in my freezer. Each household here has a large grey bin and a large green bin for waste and compost. They are picked up alternately, one each week, so if you have stinky compost, I learned the hard way to put it in the freezer until the day of pickup. My first year here, I had company and lobster of course, and put the bodies and shells out in the compost bin. In the summer heat. Because the bins are out of sight, I didn't notice until I went to take it down to the road that the whole bin was alive. It was the grossest thing I've ever seen in my life, I couldn't even touch the handles. Working at The Body Farm is definitely not in my future.
Olli
Put a small hole (about 6mm-10mm) in a piece of flat cardboard. Spread some molasses on it in a little ring around the hole. Fill a mason jar 1/3-1/2 fulll of water with a few drops of dish detergent in it. Place the jar outside away from the fly problems. Place the cardboard on top of the jar, baited side down. Will catch just as many flies as the shrimp jar without all the stink.
Vanessa
Would the soda bottle work with the shrimp? I dont like the idea of throwing away jars I can use, but a soda bottle would be tossed anyways.
Karen
Hi Vanessa. For whatever reason it worked better with the glass jars and the funnel, but you could start out by trying with the pop bottle and see if it works for you. ~ karen!
Debbie P
I marvel at your analytical skills and methods. And this is one of the most disgusting things that I have seen on the internet in a long time. Yet, it held my interest to the very end. Thank you for your blog - even if thankfully I do not suffer with bottle flies. XO
Shelagh Ryan
Cluster flies are not attracted to meat or wine so I don't have to put up with the aroma of death or having to share my wine!
However cluster flies and Asian beetles ( nasty, stinky, lady bug look a likes) love my house. The beasties are too lazy to go south for the winter but they invade every nook and cranny they can find and on a warm late winters day they emerge...I've been known to spend an hour with a vacuum trying to spot where the heck they are coming from only to realize they can fit between the casement and the window frames.
So far the best solution for the cluster flies is to ignore them and hope they find the " cluster buster". When it was owned by a small entrepreneur it was terrific. A small plastic box that stuck to the inside of your window filled with exploded egg shells that created a dust so fine that the flies could not escape. Their presence helped attract other flies. The initial investment was hefty at $20 per box and I can't say it added anything to our decor but you could get refills for each box.
Sadly the business was such a success that it was sold to a big manufacturer and the first thing they did was get rid of the refills.
Breaking the pheromone trail they leave behind seems to work for the flies...wiping the edges of the windows with bleach...but nothing seems to deter this darn Asian beetles!
Anyone have any suggestions?
I live in a rural part of Ottawa, Canada.
Claudette Macioshek
Dear God!😂😂😂😂😂You jave a wonderful sense of himour! Very informative. I live in S Africa and just CAN'T with the flies this year..am going to try this..
Karen
I was just looking back at this post myself yesterday! I'm still amazed at the amount of flies!! ~ karen
C
I had gotten one of those fly bags from lowes and 🤢🤢🤮 smelled so bad !!!!! The neighbors could smell it!😳 so I went on the hunt for something else that doesn't smell all putrid and did not cost an arm or a leg.
I got an empty pickle jar with lid ,drilled holes just big enough all over the top. Cut up maybe 1/2 a hotdog, and put some syrup in it. Worked AMAZING, with no death smell.
Karen
Good to know! A hotdog and syrup, lol. Yech. ~ karen!
Cyndee
What about apple cider vinegar for bait? I use it for fruit flys.
Karen
Flies like this require something rotting. That's why they lay eggs on manure or you see them around dead animals. So just cider vinegar won't attract them. Basically the more disgusting the stink the more they'll be attracted to it. ~ karen!
Di'Anna Bocanegra
How are you disposing the jars with the dead flys afterwards?
Karen
Hi Di'Anna - I cut the bottom off of the bottle, dump the contents into a biodegradable garbage bag and put it in my city compost bin. The plastic gets rinsed and recycled. ~ karen!
cobugi
OMG (to the image of the jar on day 14)
Karen
So gross, lol!! ~ karen!
Gusi
How do the humane fly traps compare?. The ones that catch flies but don't kill them so they can be released elsewhere.
Corey
Why don’t the flies just fly out the opening or the cone
Karen
It's too small an area for their little brains to figure out. ~ karen!
Marissa
I can’t wait to try this. We always have a fly problem as soon as my husband turns on the bbq pit. And we just got chicks, so I need to be prepared! Thanks for the post, I hardly ever read DIY blog posts I find on Pinterest (I usually just check the pics and wing it) but this was so hilarious and relatable. You rock
Renee
If you must resort to the fly strip I noticed that hanging it by the light enticed many more flies then hanging it in a corner. Mine was covered in what seemed like a hundred flys in less than a day. Just be careful not to run into it and get it stuck in your hair. Or let your cat jump from the book shelf and get her tail stuck to it. This happened to my friends cat. She was dandling by her tail and let me tale you she was freakimg out and claws were flying. Funny site to see but very tramatizing for both my friend and her cat.
Carl
We have another one that is just a squash bottle with the top cut off and inserted back into the bottle upside down - works great.
Carl
Karen,
Absolutely love this, we've done similar with cat food (that the flies laid eggs on anyway!!!) and it's working a treat
lmurr
Use the plastic bottles with paper funnel and your bait - it will work as just fine as the Mason jars.
pThomas
great article, flys are driving me crazy this year. I will def. try the shrimp, thanks! Do you also think the Brown color paper has any effect? Or is the color of the trap entrance irreverent when dealing with the powerful shrimp scent?
Paul
Canned dog or cat food works very well as bait, and isn't as strong smelling as rotting shrimp.