I had kind of a similar conversation with someone I was dating who was working with fruit flies (drosophila melanogaster)!

She knew how to make really effective fruit fly traps for that reason.

Edited to add: I replied with the methods below.

MFW I realized a fly got into the delicate machinery.

I need to know about these effective fruit fly traps. It's the height of summer and they are all over my compost bucket.

+1 the world needs to know about your ex's magic pest genocide recipe

There’s two methods. All credit goes to her so if she eventually sees this, your temporary fruit fly expertise lives on! lol

She mentioned that at the time most fly labs literally just used method 1. We personally always just used method 2 because it’s not that hard and it was extremely effective (she calls it the “nuke them from orbit” method in the old instructions email).

Method 1. You get a shallow dish/cup, or a bowl with steep walls, and put alcohol in it. Sweet liqueur works well or you can put a bit of sugar in the alcohol to make it sweeter. The fly is tempted by the thing that smells like food and they drown.

Method 2. You need narrow bottle or container that will stand up, tape, a sheet of paper, a pen or pencil, and a lure to put in the bottom to attract them. I remember the alcohol working, as above, or you can use fruit; they obviously love bananas. If you have yeast, sprinkle some on top of the fruit, because fruit flies love yeast too.

Fold the paper in half and roll it into a cone so it’s totally closed on one end. Tape it into that shape, and then use your pen/pencil tip to open the end a bit, just big enough to fit a fruit fly.

Put the lure in the bottom, and point the cone narrow-side down into the bottle. Seal the cone on well, and put it where the flies like to congregate. They’ll be attracted to the lure, but it’s nearly impossible for them to escape the little hole in the cone that protrudes into the bottle.

After a few days, fold the paper up to block the hole, or tape it or whatever, and put it in the freezer overnight. Then you can just throw the bastards away all at once!

Heh. We actually just recently had what WHS refers to as "the radioactive incident". Nothing major, but obviously at some a long time ago, someone didn't properly store/seal stuff and no one realised because no one ever goes back there.

All labs have since been thoroughly swept for exciting souvenirs from yesteryear.

I knew the dish method but not the cone solution. Gonna go do this right now! Thanks!

What worked for me is pretty simple and cheap:

• a clear plastic container that you can poke small holes into the of,
• a straight pick or equivalent to poke those holes,
• common white vinegar ($5ish for a gallon,
• dishwashing soap

Poke holes evenly in the top of lid. Put a bit of vinegar in the container (e.g. a lidded condiment cup you can probably get from your supermarket, or a fast food drink cup), add a few drops of dishwashing liquid, put the lid on and put it where the flies are.

That’s it. Scale the size of the container to the number of flies, and a clear container lets you easily see the amount of flies trapped, but doesn’t strictly need to be clear. Set up more traps if needed. Hope that helps.

My wife, then girlfriend, used to just cut a 2L soda bottle in half, then put the top half upside down in the bottom half, otherwise following the same process outlined in your method 2 instructions. It was, indeed, quite effective.

The Baxter Stockman that I shouldn't be worried about:

Cone solution works for wasps too

I have a worm farm and when the fruit flies invade, I just take a small bowl, drop of Dawn and like a 1/4 cup apple cider vinegar. After a week or so they’re mostly gone (but can hold on for a while because of eggs hatching).

This is why plastic airtight containers are superior. Dropped it? Just pick it up. Just dont put it into the autoclave tho