Ecology and Management of Diseases of Soybean That Occurred in Iowa During the 2004 Season. Part II: Stem and Root Diseases

Abstract

<p>The 2004 season growing season had cooler than normal temperatures associated with frequent rainfalls. The weather conditions were favorable for the occurrence of many soybean diseases. This season, we saw the worst ever outbreaks of white mold and sudden death syndrome, which resulted in considerable damage for many soybean producers. Both diseases were reported in two-to-three weeks earlier in the growing season than usual. Severe white mold outbreaks were found in eastern Iowa, especially from Interstate 80 north. Our quick-and-dirty survey indicates about 20% of soybean fields were affected with white mold in that region, and some fields were up to 80% infested with the fungus White mold also occurred in north central Iowa, however disease severity was less when compared with eastern Iowa. Sudden death syndrome outbreaks mainly occurred in regions south of Interstate 80 but also were found in central Iowa. Numerous reports of brown stem rot and stem canker were received from central and northern Iowa. All of these diseases are caused by soil-borne fungi.</p>