White Fuzzy Bugs In My Trees.

I filmed this yesterday in the front yard. I first found that the entire front yard was covered in the white fur strands. Then after looking at a leaf closely I found that it was a ball of fuzzy white bugs crawling all over each other. Quite strange. I want to understand more about them. They seem to be a kind of parasite, that are feeding off the trees leaves. After a period of time the the leave that these bug are living, become black and dead as if they are eating all that was good from the leaf. The leaves then fall to the ground and the insects then for a brief time eat the grass and make the ground dark in patches. I'm not sure if the fuzzy white stuff or the dark patches are a waist product of these bugs, but I must say we have an active science experiment in the front yard, that will entertain me for many weeks to come. :)