Great description of the issue.

Multi prong approach.

Some choices.

Leave cover closed.

Put in a lot of bedding then leave cover closed.

Switch around the trays.

Empty a finished or almost finished tray on top of Alfred's tray especially at the edges.

Flip the tray over into an empty tray. Maybe put down a sheet of round newspaper into it first.

I'm sure you will get lots more replies of things to try.

I've heard they're easy to vacuum. Also try one of the DIY fruit fly traps. Covering the bedding with a wet cloth (cut up t-shirt or burlap bag) helps.

Andrew

For the record, my worms live in a rubbermaid container. No trays.

Keep the entire surface of the compost covered with 2-3" of shredded paper, always. Bury fresh scraps deep in the bin. To reduce the current population of flies, use a vinegar/water trap.

Here is a link that might be useful: fruit fly trap

court; I had the same problem last fall. I tried all the tricks.What worked the best for me? What you are doing now was! I would grit my teeth and keep it up. It was not freezing so I left the bin outside for 2 weeks. The flies have not come back but it is cold weather now and they do not bother here in the winter even indoors. Hope this helps a bit.

Curt~

I also have a Rubbermaid-type container. I have had similar experiences to yours. Many methods have worked partially, but none completely -- until now. First I had a fruit fly attack. The only thing that worked somewhat was the cider vinegar traps. For the past 2 months or so, i've had a gnat infestation. Nothing seemed to work at all. Recently I discovered yellow sheets of double-sided sticky fly paper. I cut one sheet in half and hung them out over the worm bin. Within three days, they were both almost completely covered with gnats. The problem is almost over.
Now, if I could only get the mites to jump onto the fly paper, everything would be great.

Shaul

To avoid any kind of flies (usually the fruit fly or the sciaridae), with any kind of bind, a rule of thumb is to cover at least 3" of stable matter (shredded paper, compost, etc) the surface of your bin. Following that rule will minimize your chance to have an fly infestation. Another rule to follow is to not overfeed your worms.

Fly strips work for me, too. I put one right in the bin and problem solved.

When I first started my bin, fruit flies were a big nuisance for me as well. One fun and pretty effective solution (along with adjusting how I buried worm food in the bin) was getting some predatory plants. The Cape Sundew (Drosera capensis) is pretty low maintenance and can catch tons of the buggers. Since my bin is in a dark area, I use a compact florescent bulb as my grow light for my Cape Sundew, and it's flourishing.

Cider vinegar in a jar with a drop of soap to reduce surface tension. Put a funnel over it for extra effectiveness. You will see the fruit fly population be decimated in a week. To finish them off, stop adding food to your bin for at least 3 weeks. I had an enormous fruit fly problem last year and did this and they haven't come back since

I too have a massive fruit fly problem.

Its tremendous, I'll post a video. Later.

Today I tried to of the DIY traps. I chose the lazy version, where you just apple cider vinegar in a bowl or soda in a bowl.I'll let you know the results.

If this fails I also have some of these coming

http://www.arbico-organics.com/product/fly-eliminator-video/cockroaches-indoor-pest-control

Hopefully they won't eat the worms. They are pricey little creatures.

Fruit flys are attracted to the top of things. So put your wine vinegar traps up above the compost. Fruit flys also only seem to fly up. I covered my bin with a fine see through non organic material (like a shear curtain) sort of like Harry Potter's invisibility cloak. Air gets through but the flies stay trapped. I choose a pretty metalic gold like cloth that can be seen right through. The fruitflyies could easily just fly down a few inches and under the cloth and escape into the room but non bother to do that so they stay trapped.

Just use fly spray.