Effect of Foliar Fungicides on Late-season Anthracnose Stem Blight on Soybean

Abstract

<p>Anthracnose stem blight, caused by Colletotrichum truncatum, is responsible for soybean (Glycine max) yield losses in subtropical and tropical growing regions. There are inadequate data regarding the effect of anthracnose stem blight on yield in Iowa, and it is unknown if fungicide application can manage this disease. Field studies were conducted from 2008 to 2010 to determine the effect of fungicide application timing on late-season development of this disease. We also investigated the effect of anthracnose stem blight on yield and specific yield components. Fungicides reduced late-season symptom development when compared to the untreated control; however, there were no differences in yield and yield components. While foliar fungicides can reduce late-season disease development, anthracnose stem blight typically should not affect crop management decisions involving use of foliar fungicides on soybean in Iowa.</p>