Strange coating on mower deck

[ruahoo2]

Today after mowing the lawn as I was blowing the grass off of my deck I noticed a strange black soot like substance on top of the deck. I have never seen this before. Has anyone encountered this before ? I will check my belt to see if it is possibly going bad. It is not oily but more of a dry powder like coating.
Any assistance will be much appreciated. Thanks

 

[tbzep]

If it isn't mechanical it could be black mold or spores from the area you mowed. It doesn't even show much in the grass sometimes but will show up on red paint.

 

[ruahoo2]

If it isn't mechanical it could be black mold or spores from the area you mowed. It doesn't even show much in the grass sometimes but will show up on red paint.

Thank you for your answer. The mower runs great and your answer makes sense . I had thoughts along the same line and you have confirmed that.
Semper fi

 

[kraky]

The same thing happens to Yellow decks too ....LOL..... I've always attributed it to a mold or Spore too.