The bad stuff is black and gummy. dont panic, dont call your insurance
co you dont even know the true cause yet. Putting in a claim like that
could get you dropped and you might have a hard time with a new company.
A subfloor could easily get mold from moisture comming up from
underneath it is just a perfect invironment to grow, dark and damp with
wood as food. It is hard to say what to do without seeing it, is it dirt
or concrete underneath, does it flood, is the water table high, did a
pipe just leak once. Mold is common in damp places and easy to kill with
a garden sprayer full of laundry bleach. If the wood is rotted it might
be a high water table where wood never should of been used. What is
under the wood.