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Southern blight

Area of impact: Stem

Description: Causes plants to suddenly wilt and die. Light brown lesions will be visible on the lower stem just above or below the soil line. A key symptom of the disease is a white fungal mat that fans out over the lesion area but this growth might not be present in dry weather. Tan or brown fungal structures will also be visible in the fungal growth.

Pathogen involved: Sclerotium rolfsii (a fungus)

Timing/Conditions: Occurs in isolated plants late in the season and in hot humid weather.

Contributing factors: Drought conditions can make plants more susceptible. Most common in sandy or sandy loam soils.

Management practices: Rotate crops, bury soybean stubble and apply calcium or nitrogen fertilizers.

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