No, the black stuff doesn't rub off. I did go ahead and spraya fungicide on the plant, because like I mentioned, in a 24 hour period it took over basically the entire plant that was at ground level....the leaves died over night...I guess the good news is, the fungicide worked, as in, not letting it spread anymore. Honestly I was really not wanting to use anything I can't get from nature, but this is learning period and trying to absorb as much as possible as fast as possible. But, even tho it stopped it, I cut away all the infected leaves, because from what I could tell, it spread SO FAST, that I think it had to be spread by wind....so now, it's basically the vines that started in ground, and whatever was healthy that started climbing up the trellis/fencing I placed....ituse to cover that entire straw covered area, not now....I'm wondering if it will make it