John Schulz, Marriott International's director of quality control, had something to discuss last November at one of the hotel industry's biggest conventions -- something that really makes people squirm. At the International Hotel/Motel and Restaurant trade show in New York, Mr. Schulz spoke at a symposium called "Stop the Spread of Bedbugs." The pamphlet advertising the event, printed by pest-control company Ecolab, promised a discussion of "the reasons behind the resurgence of these unwelcome pests." Mr. Schulz declined to comment on his presentation, and Marriott said it doesn't have a bedbug problem. But people in the hotel industry are waking...