I came up with a theory on suburban spread.
When I take my walks at lunch, part of my route is past one of our local mega-churches. There is a field next to it, that's filled with wild grasses and wild flowers, and a driveway running down the side that separates it from the subdivision on the other side of the privacy fence. As I was walking up the sidewalk that runs around the perimeter of the field, there were about 200 grasshoppers leaping from one side of the sidewalk to the other. When I crossed the driveway where there was no wild grasses or wildflowers and just perfect green sod, I didn't see a single grasshopper. Made me wonder what kind of pesticides are being used for the perfect carpet of grass.