# Fruit fly problem??



## bio25 (Mar 3, 2018)

Hi, firstly i have to say sorry if there is this information on the forum, i found about it on it but not sure if my problem is good or bad. 

I have my Hydei culture full of eggs, but i noticed today a white mold in a few parts of the culture and im worried about it.... 





I changed all my flies to a new culture but i dont know if i can feed my mantis with flies from that culture with mold... can they stay with no feeding till tuesday ( 2 of them finished their flies today and i will order more flies tomorrow who will come home on tuesday).

Thank you for your help.


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## CosbyArt (Mar 4, 2018)

@bio25 Mold in homemade fly medium is common, and not a concern for the flies or mantids that eat the flies. From the FF culturing guide by Orin, "Mold always grows eventually but once the larvae get going they eat it all".  

Interesting you have "hairy" looking mold though, as I tend to see colored mold (often green in hue) than anything else in mine. Then again I don't bother to look at it often, and do not have to open the lid to get flies out.

I'm not sure what your medium ingredients are but there are some additives that can limit or completely stop any mold growth before the FF larvae can keep it under control.

For example many sprinkle or proof yeast (active bakers yeast, or brewer's yeast (while used/spent/dead/inactive brewer's yeast is often active, but nothing compared to active baker's yeast)) over the cultures medium with the idea the yeast will aerobically eat/mix the medium until the FF larvae take over.If you use too much yeast though (or mix it into the medium) the medium will fill with air bubbles and look like a soupy dough. Also mixing cider vinegar or white vinegar in the medium is also said to prevent mold growth, and usually done along with yeast - and I do both as well in mine.

The seemingly mold fail-safe method is to use Methylene blue (methylthioninium chloride), and is what is used in the better commercial mediums. It however is difficult to find without ordering online and costly per bottle; however, it is cheap in use though as it is just 2-3 drops per 32oz culture - see here for a source (2.303% mix).

If you buy Methylene blue from another source find out the percentage as many sell it at 1% or less solutions. The lower percentage solutions should work if you increase the drops per culture, but also means you get half the solution amount advertised for nearly the same price.


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## bio25 (Mar 4, 2018)

Thank you again for your so complete answer. I think i will try to build my own flies collector... haha

Anyway i think i will have to buy 2 cultures because i almost have an almost empty one from tuesday (12 chubby mantises eating with both hands).

I will try to post a few pictures now i had lost my fear of scape and they molted.


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## CosbyArt (Mar 5, 2018)

bio25 said:


> Thank you again for your so complete answer. I think i will try to build my own flies collector... haha
> 
> Anyway i think i will have to buy 2 cultures because i almost have an almost empty one from tuesday (12 chubby mantises eating with both hands).
> 
> I will try to post a few pictures now i had lost my fear of scape and they molted.


Your welcome, and best of luck on your build.  

Before you buy more check your cultures for pupating flies and larvae to ensure you need to buy more. Sometimes a culture will be on the verge of a booming population, even if the flies are nearly used up as feeders. If so a few days of waiting should be fine for any well fed nymphs.


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## Teamonger (Mar 5, 2018)

I have a *terrible* time with mold and I have found mixing both yeast and vinegar into my medium as well as sprinkling the top of the finished culture with even more yeast and dosing it in another capfull of vinegar to saturate the top of the medium works the best for me. I tried cinnamon but it had no effect.

I also found that Hydei cultures are far more susceptible then their smaller cousins as they take longer to get going and therefore give the mold more time to gain a foot hold.


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## Serle (Mar 5, 2018)

I have never formulated my own drosophila food just for the reasons talked about here . When I started in the fruit fly culturing I bought the 3 kg. of Repashy Superfly , certainly alot of food but 3 scoops per culture , no muss , no fuss , no mold. Anyone in for the long haul really should think about this route.......... I'm lazzy.. S


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## bio25 (Mar 5, 2018)

Thank you to all for your answers. I bought more flies cultures with their own food who will arrive tomorrow. Im thinking about to buy bottle flies but maybe they are too big yet. Right now hydei flies are a little less biger than mantis heads but i think i will try, because they eat hydei with both hands...


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## Predatorhousepet (Mar 9, 2018)

You might try stable flies or houseflies first before moving from hydei to bluebottle. The BB flies are significantly larger in size and it may take a molt or two before they are big enough to eat them. Stable flies are just a bit bigger than hydei and houseflies are slightly larger than stable flies.  The only problem with stable and houseflies is they aren't as cold resistant as BB flies so if you store the pupa in the fridge they don't last very long before the pupa no longer hatch at all (one to two weeks at most.) After a week it's best to take the pupa out of the fridge and let the remainder hatch, then just maintain the adult flies. You can feed them and they will live a few more weeks. If escapees are a problem you can hobble the flies by cutting the tips of their wings off with nail scissors, just place the adult flies in the fridge for a few minutes first to make them go dormant then you have a couple minutes to handle them &amp; do surgery before they wake up (this also works for feeding.)

For a size comparison see this pic (from mantisplace.com, she sells all these flies) from top to bottom: melanogaster fruit fly, glider fruit fly, hydei fruit fly, stable fly, housefly, bluebottle fly


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## bio25 (Mar 10, 2018)

Thank you so much, i have my pupae ready to hatch, hopefully soon...

I noticed one of my L5 (molted 2 days ago) dont eat as much as she used to.

Maybe hydei flies are really small for her, she can easily eat like 4/5 faily easily (i thought she was on L3) so i bought crickets who i will feed till monday before to give it to my mantis waiting to see if my house flies and BB flies hatch soon.


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## Kermit (Mar 10, 2018)

I used to struggle with mold on every batch. Even using vinegar,  cinnamon, yeast, etc in the mix.

Here's what I figured out.... (the hard way... and now I share!!!)

Mold typically will start to appear after 3-5 days in a fresh culture start. I have a dedicated spray bottle with 2 parts water, 1 part vinegar. Spray 2-3 bursts every 2 days for the first week and that's all you need... the mold won't survive and the culture seems to get beyond the initial  mold outbreak and progresses quite nicely from there. The flies like the hydration and they get nice and FAT!

Don't Spray too much or risk the media becoming too wet whereby the Flies cannot deposit their eggs. If you do, the culture will require a few more days to dry out before flies can start to lay eggs, only delaying the hatch cycle. It won't ruin the culture it just delays it.

The last recommendation would be that about a week before the end of the culture you can spray the culture with a couple bursts of water mist and it seems to boost the culture for an additional week or so.

I make very large fruit fly media batches every couple months. I use my 18 volt cordless drill and a blender attachment to mix the ingredients in a large bowl. Then I load them into 16 oz cups without lids and without yeast, then I stack them in the freezer. Every two weeks I pull two cups out, let them thaw overnight, put coffee filters, yeast, a blast of my 2 to 1 water vinegar solution, and fruit flies. I spray them every couple days for a week. And no issues!

? Kermit


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## Ocelotbren (Mar 10, 2018)

@Kermit Interesting idea, I am going to try it next time I'm dealing with fruit flies.  Thanks!


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## Kermit (Mar 10, 2018)

Glad to help 



Ocelotbren said:


> @Kermit Interesting idea, I am going to try it next time I'm dealing with fruit flies.  Thanks!


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## bio25 (Mar 11, 2018)

I can say for sure mold was produced by the moisture + heat (23°C).

I tried to give crickets to my paradoxa but they dont even look at them.... I will be feeding them with FF until the bigger ones emerge from their pupae. L5 is really big forr FF and they need to eat tons of them.


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