Your post caught my eye from the homepage.
I remembered that Bert McCarty, Ph.D., talked about quackgrass in the webcast he taught for us earlier this year (it is called Options for Your Weed Control Plan and is available free On Demand here
http://www.gcsaa.tv/webinars/education/view.php?id=232)
I did a quick look and his slide says:
Quackgrass[list">Cool-season rhizomatous grass that forms thin patches,
Has characteristic long-clasping auricles,
Selective control is currently unavailable,
Spot treat with Roundup when the grass is green and growing (not under drought stress) and resod (sorry).[/list:u">
I didn't see anything on orchard grass - he has a lot of other good details, however.
I looked at Today's Turf is Fescue which Steve McDonald taught for us in March 2013 and it has some mention of orchard grass. That recording is here:
http://www.gcsaa.tv/webinars/education/view.php?id=187Steve might be a good contact to ask if you don't get what you need here. Lisa