Last spring I planted swiss chard and it did very well except for a brown wilted (fungus)? that starts on the leaves and spreads.

I have planted a new fall crop of the swiss chard and also spinach and beets. I planted in a different part of the garden and new soil. The leaves of the young plants are getting this brown/white wilted disease.

Does anyone know what this is and how to control it?

Thank You, Pinkerpie