Mold or yeast overgrowth

Discussion in 'Food & Feeding' started by VivSenc, Feb 27, 2016.

  1. VivSenc

    VivSenc New Member

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    A couple of times when I made fruit fly cultures, I noticed that some of the media looks slightly discoloured and a bit powdery looking up close. It does not smell foul and the flies don't appear to be bothered by it. I do see tiny larvae on the sides of the cup. I am wondering whether or not this is a type of mold.

    The media formula is what Understory Enterprises suggests on their website for making homemade culture media. It is made up of equal parts unsweetened applesauce and mashed banana, whole oats and yeast. The recipe calls for a tablespoon of yeast and to sprinke some on the surface but I only use a teaspoon and I sprinkle a little bit on the surface. This mold-looking stuff only appeared in my hydei cultures and I've never had it happen in a melanogaster culture. In the photo I included, the darker coloured media toward the bottom of the photo is the normal colour whereas the stuff toward the top is the discoloured powdery stuff.

    Has anyone else experienced this and know whether or not its mold or just yeast and if its harmful?

    thank you!
     

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  2. mystah

    mystah Legendary Member

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    I find my Hydei cultures get a little More like a Petri dish then the Melos.

    I usually find that it goes away once the culture gets going

    You can try adding a little vinegar to the culture. It may help with the mold
     
  3. erikm

    erikm Administrator Staff Member

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    Certainly looks like mold. I don't believe it's 'harmful' but it is not beneficial either. It may reduce efficiency of the culture.

    Curious why you don't use a tablespoon of yeast when that is what's recommended? :)
     
  4. VivSenc

    VivSenc New Member

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    I tried making with only a teaspoon because I had issues with having all of the flies die after putting them in due to the yeast suffocating them. With a tablespoon, I would leave the culture open for a day like the instructions say to allow it to breathe while the yeast does its thing but leaving it open for a day didn't seem to be enough because all the flies quickly died. Maybe I had too much or not enough media in proportion to yeast, I don't know. I found that a day with the culture open with a teaspoon of yeast didn't cause the flies to suffocate when put in the culture. Maybe I'll try a tablespoon again but wait two days. I also tried it this way to save on yeast to save some money.

    Strange that I never had this mold thing in the melano cultures. Maybe it's got to do with the increased fly traffic from the start due to the faster lifecycle.

    I might try using vinegar like Mystah suggested or just go back to what the original recipe says to do and just wait longer before putting flies in.
     
  5. Ron Jung

    Ron Jung Contributing Member

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    The pictures doesn't come up here but it seems you have your answer. I use brewers yeast for nutrients but don't use bakers yeast as CO2 is released in the first days. If you are having problems I have my own receipt that I mix 50/50 with Repashy and could sell you some to see if you like how that works. If you are interested please email me directly. I use more expensive stuff in my medium but it is more nutritious thus the flies are better fed and so are the frogs. I tend not to skimp when it comes to my frogs.

    Ron.
     

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