Culture crash -- excelsior?

[ZenMonkey]

I've been making very successful FF cultures for a few months now, just massive amounts of flies. When I throw away old cultures I could probably still feed from them.

Unfortunately, my last two cultures have both, surprisingly, crashed. I don't think it's mites, can't see any and I also recently revamped my culture cabinet, including new mite paper and spray in the drawers. Nothing else at all has changed as far as my culture-making, and the only environment change has been a slight increase in humidity.

Is it possible to wreck a culture by poor use of excelsior? It's the only part of the process I seem to suck at. One culture had pretty clean sides and then, the next day, lots of little larva casings (or whatever those things are) and even larva all over the sides. The crashed cultures were both ones where I think I used too little excelsior.

Hoping like heck my new third culture (which I made just before the crashes) booms, or that the many live maggots in the crashed cultures eventually grow up.

[Philsuma]

Excelsior can cause MOLD - black mold from spores on the wood (excel) but the shavings in and of themselves could not effect production like you are describing above.

My guess:

You are taking flies to seed the new cultures that are not as 'sexually prolific' for lack of better terms. Even though there has been more than a few threads on 'when to pull seeder flies' , other than NOT within hours of the first hatch, that's all I know.

sometimes FF production is hit or miss for inexplicable reasons. It's ;mad science; .lol

[ZenMonkey]

Yeah, I do wait until a culture's in the midst of its cycle before I pull, which has worked fine until now. Good to know about the mold; I've been using a little vinegar in my cultures to stave that off, but I didn't realize it was because of the excelsior. I haven't seen anything like that though.

About the mad science, I have definitely gotten that impression from reading quite a few "WTF happened to my flies?" threads here and elsewhere, but just wanted to make sure that I hadn't erred by not providing enough area for eggs. Is it better to err on the side of too much or too little excelsior, if one must err?

[Philsuma]

The excelsior is mainly to provide 'living' area for the flies - room to hide and walk, ect. I like it because it has a wicking effect and somehow, magically enables the best moisture levels in my cultures. I went a whole year without excel and then switched back and i'll never do without it again. My cultures do much better with excel - just my preference.

[ZenMonkey]

I definitely agree about the wicking effect. Though it's usually very dry here in So Cal, between that and the Sterilite drawers, I haven't had to mist my FF cultures more than once in a very long while.