Sudden death syndrome
Area of impact: Stem and roots
Description: Scattered pale spots appear between the veins of leaves and later enlarge to become brown lesions surrounded by pale areas. Leaves may be cupped or curled and detach from stems as the disease progresses. Roots will rot and develop gray areas inside. The pith will remain white—this is a distinguishing feature of the disease.
Pathogen involved: Fusarium virguliforme (a fungus)
Timing/Conditions: Plants are infected in early season but symptoms don’t occur until pods start to fill.
Contributing factors: Early planting; cool wet soil; early maturity; and high-yield conditions. Soybean cyst nematode is often associated with this disease. Overwinters in soil.
Management practices: Plant resistant varieties; improve soil drainage and minimize compacting; reduce nematode populations; stagger planting dates.