Frogeye leaf spot
Frogeye leaf spot is a foliar disease of sporadic occurrence in NY, and though it may be found in most soybean production areas of the state, it is rarely at epidemic proportions. The disease is favored by warm, humid conditions. Symptoms include distinctive leaf spots which start out with dark brown to black centers surrounded by red-brown margins, but the centers of the lesions eventually become light gray/brown with the red-brown margins. Sporulation may be visible in the centers of older lesions when humidity is high. The pathogen survives on soybean residue. The pathogen has developed resistance to QoI (Strobilurin) fungicides throughout soybean production areas of the country. Because disease severity is often low in NY soybean fields, fungicide applications may not be cost effective for management purposes.
Resistant soybean varieties are available and should be planted in fields with a history of this disease.