Don't worry about the bees they will not be harmed by visiting your moldy bee balm. The important issue is why your perennial plant is getting mold. Most likely damp, warm weather is causing the problem. Good air circulation, sunshine and good drainage will help to control any fungus among us. Once the flowers fade you can cut the plant right down to ground level and see if it comes back clean. If not, give it the shovel solution. Dig it up and plant something else. Life is too short to put up with ugly plants. Keep growing, Marianne Binetti