Here are some pictures of Mustard Seed Fungus, Southern Blight, or Crown Rot... I notice it first when cleaning dead foliage off of clumps.. Dried leaves and rotting leaves have a different feel when they come off, and definitely a different look. So some of the shots are what the leaves look like, and then there are close ups of the sclerotia ("mustard seeds").
These show the "mustard seeds". They start out white, then age to brown. The white cottony growth can spread to the soil, so I'm guessing, the earlier it's discovered, the better.
The surest sign that intelligent life exists elsewhere in the universe is that it has never tried to contact us.