TOM KAN PA said:

My brother has it. And he says there's really nothing you can do about it.
What is it? What causes it? And is there anything that can be done about it?

It's a fungus, doesn't overwinter well in very cold climates, and the best
solution is to fertilize the grass and keep it growing vigorously.

I haven't had it in my lawn until this year, when the 'restoration' after the
street paving involved bringing in really poor, sandy dirt with a thin layer
of weird, black crusty 'top soil' and then hydroseeding. One patch of cooler
than normal, moist summer weather and whammo! the new grass had this
disease. Mow the infected area separately from the rest of the lawn, wash off
your shoes and mower afterward, and apply a slow-release organic fertilizer
on the rust infected area.

We are so dissapointed with the 'restoration' that the township has not signed
off on the project and we are not yet being billed for the paving project.

See the following selection from the MSU extension service:
http://www.ipm.msu.edu/CAT03_land/L08-08-03.htm#5

--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)