In the last two seasons, soybean rust has shown limited dispersal during a growing season in the southern US. In summer, it mainly spread in the Gulf Coast states. Dry weather conditions in past two summers have been considered as a possible reason for the slow development of this disease in the US. The disease did not take off to the further northern states until September. This year it was found in three new states, Illinois, Indiana, and Virginia. So far, it was found 15 states in total242 counties (See the map on right). In Iowa, the disease was not found in sentinel plots by the time of frost come despite of the efforts using soybean rust test kits later in the season. Many people wonder why the disease is so devastating in South America but moves so slowly in North America, which is not consistent with anticipations concluded from the literature. New insights from recent research have shade light on this disease. Below is the review and summary what we have found.