Party buses are a particularly bad idea for "the already densely crowded Old City area," he wrote, "which is already struggling to regain a good reputation as a desirable night time entertainment destination."
The stern letter was a "proactive step" to get the attention of any Old City nightspots who work with promoters that bus in student revelers, Korn said.
The party buses and the unruly crowds they attract damage the strides Old City has taken in recent years to build a reputation as not only a place to drink, but to eat, shop, take in theater, and live, Korn said.
The "honky-tonk fraternity atmosphere" is not something Old City wants to foster, he said.
Although he did not name specific establishments in his letter, Korn said that an anonymous tipster contacted the Real-Time Crime Center Friday with concerns about college-aged students arriving in school buses at the Tantra Luxe Lounge near Third and Market Street Thursday night.
Korn said he had received no other complaints about Tantra, and it was unclear if the buses were part of a bar-sanctioned promotion.
Tantra is closed Mondays and numerous attempts to contact management were unsuccessful.
Copeland of the Special Service District, a business improvement organization, said starting last year he received several complaints from Old City residents about the party buses.
"We are doing everything we can to work with bars and restaurants to address the issue in a collaborative way," he said.
The district provides uniformed security staffing and "safety ambassadors" that work to serve as "eyes and ears" to the police, Copeland said.
Korn, who has commanded the Sixth District, which includes Old City, Spring Garden, and portions of Northern Liberties, for 15 years, said college party buses have caused headaches in the past, usually at Spring Garden area bars like the now defunct Tiki Bob's Cantina.
Korn said that unlike the annual Erin Express bar crawl - which is an organized and coordinated event - the party buses catering to the "fraternity crowd" lead to large, sometimes unruly, crowds without warning.
The message to bar owners is simple, he said.
"If you're doing it, or thinking about doing it, please stop," he said. "And if a bus of college students show up at your door, tell them, 'no.'"
Contact staff writer Mike Newall at 215-854-2759 or Newall@phillynews.com.