m0useanswered grow question 3 years ago You could try to spray the outside with peroxide but with that style of feeding you can't really stop it.
Its living off of the excess feed soaking into the fabric. I don't see it harming the plant any. But excess peroxide soaking though the fabric could harm the roots.
So use it with caution.
Other option is to increase the airflow aorund the pots so its not as moist and it may die back.
Good Luck!