No, Rescue™ Disinfectants can not be used to disinfect real grass.
Rescue™ disinfectants are designed for use on hard, non-porous surfaces such as exam tables, stainless steel, many types of flooring, and most plastics. There is no EPA-approved test that we could conduct to determine whether Rescue™ (or any other disinfectant) is effective on grass areas.
You may also find these resources useful: