Pull the moldy cutting.

No more watering. Leave the bottles on the jugs and the tops on the bottles and don't mess with them. Check from time to time to make sure that there's at least a little bit of condensation inside the bottle, and remove any fallen leaves.

The beauty of the bottle method is that you can leave the bottles alone during the rooting process. It sounds to me like there's too much moisture in your bottle, creating a perfect situation for mold. (Sometimes cuttings mold anyway ... nothing is 100%, and stuff happens.) What rose is this?

Connie

Abe Darby. Didn't realize that I did not need to water them as long as there was condensation. Thank you!!

You might consider treating your cuttings with hydrogen peroxide before striking them. It's slightly acidic and might help "sterilize" them against any pathogens you may bring in on them. Connie is right, ANY condensation inside the bottles raise the humidity, preventing them from drying out. But, too much drowns them, inducing mold. Kim

I also would consider trying coco coir instead of potting mix. Very cheap, just stay away from pet stores and find a good hydroponics place to buy from.