Soybean Rust Update - May 13, 2009

According to colleagues in the southern States, soybean rust has survived continuously this winter on infected kudzu in parts of Alabama, Georgia and Louisiana. This is in contrast to other years were there has been a break in detection at some point during the winter months most often due to cold (frost) weather conditions resulting in kudzu defoliation. The result has been the earliest soybean rust has been detected in some areas. The weather conditions in the Gulf states region has been favourable for disease development, as the most recent infections in the panhandle of Florida illustrates. If favourable conditions continue, they expect new infections in the region but again this will as mentioned greatly depend on the weather conditions over the next couple of weeks.

What is the risk this year? Of course it is too early to come to a conclusion based on the early information. Early infection in the south in conjunction with a potentially delayed soybean crop in Ontario and other parts of the northern soybean production area however could pose problematic but as in recent years conditions could turn dry quickly in the southern US Gulf States. Time will tell but be assured we will continue to monitor the situation.

Figure 1 - Soybean rust scouting continues in the Southern U.S. and Mexico. Soybean sentinel plots continue to be established in the Gulf Coast states and kudzu is breaking dormancy throughout the region. In 2009, soybean rust has been found in five states and 17 counties in United States, and in two states and five municipalities in Mexico. (Source: USDA ipmPIPE at http://sbr.ipmpipe.org/cgi-bin/sbr/public.cgi)