Biology and Management of Premature Yellowing and Death of Soybean Caused by Phomopsis Idiaporthe Fungi
In recent years, there is an increasing interest in premature yellowing and death of soybean during a growing season. To some growers, premature yellowing soybean has become a production problem to their efforts to stabilize yield. We have received more and more questions why soybeans turn yellow prematurely. Few years ago, the problem was mainly from eastern Iowa and now soybean samples submitted to ISU Plant Disease Clinic come from every region of Iowa. People have called such a problem top dieback or tip blight. Typical symptoms of diseased plants are yellowing of top leaves, often followed by brown margin on the leaves. The problems are caused by a group of closely related fungi, which can cause Phomopsis seed decay, top-dieback, pod and stem blight, and northern stem canker. This article discusses the biology and management of this disease.