No. 21 Article 4/August 15, 2008

Sudden Death Syndrome Symptoms Beginning to Appear in Soybean

Symptoms of sudden death syndrome of soybean (SDS; caused by the fungus Fusarium virguliforme, formerly known as Fusarium solani f. sp. glycines) are beginning to appear in some soybean fields in Illinois. Initial symptoms appear as light-yellow flecking on the leaves. The yellow areas enlarge to cause interveinal chlorosis (yellow leaves with the veins remaining green) and eventually interveinal necrosis (dead leaves with the veins remaining green). These foliar symptoms generally do not appear until the soybean plants are into the reproductive growth stages (July and August).

Although SDS symptoms appear on the foliage of the plants, the Fusarium fungus that causes SDS actually infects the soybean roots early in the growing season. The foliar symptoms of SDS are caused by a toxin that the fungus produces, and the toxin then moves upward in the vascular system of the plant.

Initial foliar symptoms of sudden death syndrome appear as yellow flecking on the leaves.

Interveinal chlorosis and necrosis of soybean leaves with sudden death syndrome.

Unfortunately, there are no silver bullets available to control SDS completely, so using multiple management practices is encouraged to help limit its damage:

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