Fruit Fly cultures dying - turned black

[cleigm84]

Help...

I have had a fruit fly culture consistently producing for the last 2 years. I moved to Florida and now they are all dying including the 4 new ones I ordered from Josh's Frogs. The fruit fly media stays damp and everything is good temperature wise in my apartment. The temp is consistently around 75 inside and humidity is good. I find that the cultures turn black and all the flies in it die within 2 weeks. What is going on?? I have never had this problem before.

[Philsuma]

What fly species - Melanogaster or Hydei ? Sometimes Hydei, with their longer growth cycle can be detrimental to some individual hobbyists routines. I like Melanogaster much better, overall.

Whenever you relocate, you have temperature and humidity variables to deal with. Florida is a state that is much more humid than many others...and warmer. Got to factor those in.

75F is a good temperature

What recipe is your media and do you have anything inside the cx's like excelsior or other?

Offhand, I'll guess that you are having mold issues - the 'black stuff' due to Florida and increased humidity ect.

[cleigm84]

They are melanogaster. I'm using the pre-made josh's frog media that is 1/2 cup boiling distilled water - 2/3 C media. There is excelsior in the culture cups etc.

[Philsuma]

Some excelsior can get mold spores. Excelsior, being shaved wood, is especially susceptible. The excel may look ok but it fact is carrying spores. Florida and it's high humidity is at work against you here as well.

Do you have a Fabri cote / vented lid ?

Are your cx cups glass or plastic?

Are you noticing death and black stuff in under 30 days? Under 15 days?

You may have to obtain some new flies and start over from scratch.

[cleigm84]

As I stated in my earlier posts I have been doing this successfully for two years with the same culture. That culture completely died on me a few weeks ago and I ordered 4 more containers with producing cultures. Those are pretty much dead as well. From what I've seen it's under 20 days. My cups are plastic

[Philsuma]

A pic or two may help, but again, if you see 'black stuff' in the media and /or excelsior...then I'm fairly sure that is mold.

Mold can be transferred by proximity - touch or even airborne. It's possible the location or room that the flies are located in may have mold.

[Philsuma]

vented lids?

[cleigm84]

Yes I've been using vented lids. I haven't changed any thing in the 2 years except moved from NY to Florida. My question is how do i stop this as I currently don't have a steady supply of flies. Is there a special box or kit I can buy that will keep Temps, humidity regulated etc.?

[joneill809]

Other ideas - mites or insufficient air flow?

Perhaps you're seeing higher mite populations due to the RH changes from the move Phil mentioned. I don't know if this is the same for you, but this is the time of year in my area where the humidity spikes and mite populations take off. I've got to be really careful about mite control if I want to keep my yields up in the spring. My cultures, both hydei and melanogaster, can take a hit this time of year if the little buggers get in to the cultures and explode as the RH increases from winter values of ~30% spiking to 50% to 60% in the spring when the storms start rolling through.

In terms of control, food grade Diatomaceous Earth works well. You could try mite paper too. I dust and sift flies to try and separate mites from seed flies too. I don't see many of the traditional, larger mites anymore that you can see crawling if you look closely, but I do see blooms of super tiny "dust-like" mites that you can only see when their carcasses pile up on the DE. Not sure what you're doing on the mite control front, but those may be ideas you can pursue if you suspect that might be an issue.

The other thing to check is ventilation. Are the flies / maggots clogging up your vents? Sometimes they slime up the fabric lids when the humidity increases and I don't get enough airflow into the culture.

[joneill809]

Oops I see the turned black reference. Discard the mite comments. Maybe venting / airflow then?

[Philsuma]

There is no quick fix. I would ditch all the excelsior and go with bare cups and media for now.

Decide if a new location in your house is something to consider.

Put a wanted advertisement asking for local hobbyists to provide some flies or local ideas. There are a good amount of hobbyists throughout Florida.

[MELLOWROO421]

A vendor you mentioned sells cups that have small holes punched in them instead of a fabric coated vented lid. If you happen to be using those cups, that may be the issue as well. I unknowningly purchased those lids and the humidity levels in the cups spiked drastically causing issues with all of my cultures that had the new style lids on them. I would recomment the fabric covered lids if you are not already using them.