By Jaime Cummings – NYS Integrated Pest Management Program
It has been an optimal year for sudden death syndrome (SDS) in some parts of New York State. Reports and diagnoses have been received in western and northern NY fields. This disease is favored by cool, wet spring conditions, followed by hot and dry weather. The infection occurs very early, at germination and emergence, but symptoms rarely appear before reproductive stages and pod filling. Symptoms are most obvious as interveinal chlorosis on the leaves, and can be confused with other diseases that have similar foliar symptoms, including brown stem rot and northern stem canker. Splitting the stems of an SDS infected plant will reveal a white pith with discoloration of the vascular tissue of lower stems (see photo).
Few varieties adapted to our region are available with moderate resistance to this disease, and rotation is not very effective since the pathogen can survive for many years in the soil and on other crop debris. The ILeVO seed treatment has shown good results in trials from other states, and may be your best bet for managing SDS in fields with a history of the disease. Improving drainage and compaction and delaying planting until soils have warmed up, in addition to planting moderately resistant varieties (where available) with seed treatments, are good IPM practices for fields affected by this disease.
It’s also important to note that there is a synergistic effect of SDS and the soybean cyst nematode (SCN). If you have a field with a history of SDS and lower yields, this would be a good candidate for SCN testing. We are approaching the optimal time to take soil samples for SCN testing. There are many public and private labs available for SCN testing. The Cornell plant diagnostic clinic offers this service, and there are a number of labs and clinics that specialize in this service and accept out of state samples. The most highly recommended testing facilities include the University of Missouri SCN Diagnostics lab, the University of Illinois Plant Clinic, and Midwest Laboratories. Please see a complete list of testing labs and other information on SCN provided by the SCN Coalition: