A de facto strike has hit production of The Simpsons, with the key actors providing the principal characters' voices, Dan Castellaneta (Homer), Julie Kavner (Marge), Nancy Cartwright (Bart), Yeardley Smith (Lisa), Hank Azaria (Moe) and Harry Shearer (Mr. Burns), demanding raises from about $360,000 per episode to $500,000, Daily Variety reported today (Tuesday). With the actors refusing to record the dialog for upcoming episodes, production has been on hold, and it now appears that fewer episodes than the usual 22 will be turned out for next season, the trade publication said.