Small Aircraft
Air Traffic Control Fully Certified
Confusion
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Gate
Airport; Human Factors
I was working Ground Control 1+2 combined at the time of the event.  During a scan of the movement area I noticed a plane on Taxiway Papa moving eastbound who I had no communication with. I reached out and stated; 'Aircraft on Papa; say call sign.' No answer; tried again and no answer. I had an Operations vehicle in front of the airplane that pulled off the taxiway when he heard me reaching out to the aircraft. I asked Local 1 if he knew who the aircraft was and he stated no.  Local 2 realized it was his aircraft in the pattern who landed on the taxiway. Local 1 instructed the pilot to stop and contact Ground. I read him the warning and he wanted to go back to the runway.  I issued taxi instructions and then ask him if he realized that he landed on a taxiway and the pilot stated no.  He then requested to go back to the Ramp.  I canceled taxi instructions and issued him new instructions.  At this point it started to set in and he requested the Operations vehicle to escort him back to the Ramp.  Pilot was not ready for solo.  No warning before landing on taxiway.  Runway separated by less than 2;500 FT.
DAB Ground Controller notes an aircraft on Taxiway P that he is not talking to. Local 2 informs Ground that the aircraft is his and was supposed to have landed on Runway 7R; but instead landed on P.