If it gets to the point where the plant is getting overwhelmed, or the stems are affected down to the soil level, you'll want to go ahead and dig them up. Trash the remains, don't compost.
Also, mulching your beds will help with splash up from the dirt. Dirt is the source for many of the fungal infection we see in plants. Straw, or leaves, grass clippings...
USDA Zone 7b/ Sunset Zone 31