Hmm, y'all got me thinking...
I already have compost, neem oil concentrate and spinosad so I am going to prepare some materials then layer on the following:
-A good feed
-A heavy top dressing of compost mix treated with strong neem oil drench (letting the drenched compost dry out to just moist before use
-Even more paper bedding likewise drenched with spinosad then dried to barely moist.
-Mozzie net the lid
Then leave for 2-3 weeks and see what happens.
I'm not quite a seasoned worm farmer yet but I've had one going on a year now and I am inclined to say that those bolded items above cant be good for the worms or the soil your adding the castings to eventually.... Do you get a lot of worms trying to escape out of top of the bin? If so this is a sign they arent happy with whats going on in the bin usually but I'm thinking you know that.
What kind of bin/setup are you using? I use these giant 27 gallon black totes with yellow tops in a manner similar to the green worm factory thing with the drain on the bottom... the one that has all the different levels where you fill a level with your desired composting items, insert worms... put another tray in that has holes in the bottom of it for the worms to get through; fill with bedding and feed, then its placed inside the bin that already contains my worms right on top of them. As they finish up the first/bottom tray, they migrate up to the next one with the new feed and so on...,,
The point I was trying to get across albeit not so well spoken or formatted; is that with a worm farm and (real) organic growing.... you are creating an environment that couldnt be any better for creating
life in general as well as the containers; from the bacteria and fungi, all the way up to the worms... so its going to promote all the other life in between.... so a fruit fly or gnat isnt the worst thing to happen...
All that shit your adding cant be beneficial to the worms... I understand your treating the stuff and letting it dry (effectively reducing the strength of it which assists the bugs in building resistance) and all that, but its still getting to your worms, and eventually your soil... Your better off leaving things like spinosad or whatever else your adding (the oils specifically) out of your grow unless ABSOLUTELY necessary.
If your soil is on point with bug prevention (I.E. neem cake/meal, nematodes.... DE, and of course worm castings which naturally carry nematodes, protozoa and other things to help keep soil borne bugs and nasty shit in check), your grow room is clean, and you are freezing your refuse..... you should be in good shape... If they keep coming... Try to figure out the source... If your freezing your stuff prior and your still seeing a lot of gnats/fruit flies.... maybe they're coming from somewhere else, in which case you need to track down what and or where they're coming from and deal with them.....
I understand in the world of weed growing, likely starting where we all did with chemical ferts etc.... we dont like bugs.... at all.. I get it... I fuckin hate them too, but when you have a good organic eco system going on, a fruit fly and or a fungus gnat is going to pop up on occasion because life happens when the proper conditions are promoting it, however... as i stated above if your soil is prepared for these critters, they're going to leave it alone or be handled by it...
If you feel the gnats are a serious problem where they're getting stuck in your buds, because aside from their larvae growing in your root zone and the problems that go along with all that (if your soil is prepped..... this wont be happening), getting stuck in your bud is about the worst their gonna do....
The weather is getting nicer as of late so maybe you could setup a different location outside or something, or just outside your grow room if need be/possible. But I personally think you are over reacting with the neem oil and spinosad... sticky traps as a notification/monitoring device but other than that I wouldnt be putting any kind of oils or bug kill juice into your worm bin at all, its supposed to be natural and organic and what not, even though neem oil is basically organic, its not something I'd let touch your soil or anything thats going in your soil....
After adding that shit you may open up your worm bin and find that only the fungus gnats and fruit flies are alive...
Save all that for a real emergency because the more you apply spinosad, neem oil or the like without completely killing the population, your building up their resistance to whatever your trying to kill them with, and now you have it permanently in something you plan on adding to your soil...
I dont know how close you keep your worm bins in reference to your plants but I grow in 2 separate tents in one room, and the room next door is my "work room" where I keep my worm bins, my water source, soil.... etc... that room doesnt have a door on it so anything bugwise that pops up in either room is going to make it into the other room eventually... I mainly have bug issues when I have to bring in new soil into my grow, than I do with anything from my worm bin. Any and all bagged soil by roots organics, fox farms... anything other than straight coco coir thats "sterile" seems to come pre-charged with bugs right out of the bag so start thinking about a way to treat all your soil like I stated above with the nematodes and all that.
The only real way is to get your soil prepared and ready to kill anything that plans on laying eggs in your soil (A dusting of DE on your containers of soil/neem cake) and/or killing the eggs once laid (nemetodes and neem cake), as well as getting your soil properly ready to support healthy plants from beginning to end, along with a clean grow room and you'll have nothing to worry about even if you do see a gnat or fly here or there because its not gonna live much longer and wont be reproducing.
Good luck either way and let us know how you make out...