"Temperatures well above 100 F will kill mold and mold spores, but the exact temperature required to kill specific species is not well established."

Frequently Asked Questions About Mold - links to EPA and CDC here also.

You would think vaping temps of 350-400F would certainly be "well above 100 F", but as stinkyattic said, you're drawing air through the moldly herb before it all reaches that temp range. I say better safe than sorry.