A new trade agreement will remove the duty on U.S. wines exported to Korea, a growing market for California vintners. The agreement, announced this week by U.S. Trade Representative Ron Kirk, will take effect March 15. Korea’s import duty on U.S. wine is currently 15 percent. Korea is the 10th largest export market for U.S. wineries. Last year, U.S. wine exports to Korea rose to $12.6 million, up 13 percent from the previous year, according to the Wine Institute. Volume increased 1.6 percent to 381,000 cases