Numerous cases of Frogeye leaf spot have been reported in fields of susceptible soybean varieties.
Circospora sojina is the fungus that infects leaves, stems and pods. Warm, humid and rainy conditions favor rapid development of infection. Infection may take hold anytime during growth and development but is most commonly found after flowering and in the upper canopy. Where disease pressure is severe on susceptible varieties, yield losses of up to 30 percent may occur.
Foliar fungicide application may be warranted where threshold levels have been reached or exceeded.