Today I noticed some Black powdery stuff on leaves of my Crepe myrtle. I
had sprinkled seven dust on them about 25days back to protect it from
Japanese bettles. But don't know if it was washed away completely from
the previous rains! Could that powder be turning black now, or is it
some kind of fungus/mildew etc?

I have googled for it and have found a website, but its not what I have:
http://msucares.com/newsletters/pest...s/19980519.htm

Thanks.