Thread: Removing moss from lawns & Tree bug

Howdy folks,
What is the best method for eradicating moss that is growing in a lawn, other than removing the trees, and, does the Ph level have something to do with it too? The ground is hard and doesn't soak the water in real well and the area in question only gets afternoon sunlight during the summer\hot months of the year.
The 2 trees which lose their leaves in winter, seem to have some type of bug on them which turns other plants up to 15 meters away black or dark brown and some of them die. They themselves (the trees), have a black unnatural colouring and certain times of the day one can see a shower of sorts coming from the branches falling to the ground. Park one's car under them and its quite difficult to remove the sappy dark crap. Ants love it too. The same trees line the street which were planted by council and have the same problem.
Geraniums seem to be immune to this and don't go off colour.
Any help would be appreciated,
Thanks,
Mark.