Sclerotinia stem rot
Area of impact: Stem
Description: Lesions appear at stem nodes during or after flowering and eventually expand. Infected areas are soft and watery and in moist conditions covered with a white mold. Plant tops turn gray then wilt and die. Hard black fungal masses appear on or inside stems and pods.
Pathogen involved: Sclerotinia sclerotiorum (a fungus)
Timing/Conditions: Occurs after flowering and only in cool moist weather.
Contributing factors: Narrow rows high fertility lack of air circulation under the soybean canopy early planting and high plant populations. Overwinters in soil or in infected stems.
Management practices: Use uncontaminated seed, avoid irrigation until seed has set, select less susceptible varieties. Foliar fungicides may not be economically beneficial.