Foliage symptoms begin as scattered yellow blotches in the interveinal leaf tissue. These yellow blotches increase in size and merge to affect larger areas of leaf tissue. Veins typically remain green. The bright yellow blotches between the green veins give affected leaves a striking appearance. The yellow areas may turn brown. As the interveinal leaf tissue turns brown, it also dries out. Upper trifoliolates become brown and dry out. Severely affected leaflets may drop off the plant, leaving the petiole attached or they may curl upward and remain attached to the plant. Infected plants may wilt and die prematurely.

Root systems may show deterioration and discoloration of lateral roots and taproots; a blue mold growth may be evident on rotted taproot and roots. When split open, internal tissues of taproot and lower stem may show a light-gray to light-brown discoloration. SDS is primarily a root rot disease with foliage symptoms resulting from a toxin produced by Fusarium solani f.sp.glycines and plant tissues.

SDS has been associated with maximum yield potential soybean production, that is, fields with optimum fertility, irrigation and lime application. Field observations suggest that SDS is more likely to occur and to be more severe with high soil moisture, whether that is supplied by rainfall or irrigation. SDS is also more severe when plants are stressed by other diseases or environmental conditions.

To manage SDS select varieties that have performed well where SDS has been a problem, improve drainage in poorly drained fields, avoid compacting soils, stagger planting dates or delay planting until soils are warm and dry, rotate crops, maintain good crop vigor and harvest fields with SDS in a timely fashion.


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