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Brown spot

Area of impact: Leaves

Description: Tiny dark brown spots develop on leaf surfaces and later merge to form irregular brown patches. Infection starts on the lower leaves and works its way upward; infected leaves turn brown and drop.

Pathogen involved: Septoria glycines (a fungus)

Timing/Conditions: Occurs in early season when the first true leaves appear. Later it spreads to other plant parts. Prefers warm wet weather.

Contributing factors: Continuous soybeans and minimum tillage. Overwinters in infected plant debris and can be seed transmitted.

Management practices: Rotation with non-legume crops tillage and fungicides.

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