Q.growing brussel sprouts
All of the plants have what appears to be a black fungus. What do you think is the problem and how can I correct it? Or do I have to take them all out?

Certified GKH Gardening Expert
Sounds like you have either black spot or sooty mold. YOu don't need to remove the plants, but the fungus may affect the quality of the produce.
These articles may help:
https://www.gardeningknowhow.com/plant-problems/disease/black-spot-fungus.htm
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm