Tobacco blue mold disease, caused by Peronospora tabacina, is a yearly threat to leaf production in many of the 95 tobacco producing countries of the world. The long-distance movement of inoculum and explosive nature of the epidemics requires an international understanding and cooperation on the biology, epidemiology, biometeorology, control strategies and impact assessment of this dangerous disease. Research data and control developments based upon a comprehensive research program in North Carolina and other cooperating countries will be discussed. Emphasis will be placed upon warning and forecasting systems related to short-term emergency measures necessary when blue mold is first reported. Long-term control strategies will also be discussed.