Monitor Soybean Pod and Stem Blight

Pod and stem blight is found throughout most U.S. soybean-producing areas, and harvest is the time to check for pressure. Harvest is the time of year to check your soybean crop for signs of pod and stem blight. Check for signs of disease now because combining infected fields sooner rather than later helps reduce pod and stem blight pressure, especially when harvest is delayed due to wet weather.

Caused by the Diaporthe and Phomopsis fungal disease complex, grain damage of 2% or more reduces the grade of the harvested soybeans and thus profitability. This fungal complex infecting soybeans can cause liver damage in chickens and a reduction in the quality of oil, flour and other products.

• The infection is only visible on dead plant tissue.
• Stems develop linear rows of black specks, known as pycnidia, or fruiting structures.
• Pods may be infected and show scattered pycnidia specks.
• Infected seed appears shriveled, cracked and with a white, chalky mold.

• Fungal pathogen overwinters on infected soybean or other crop residue.
• Infection usually occurs early in the summer from water splashing spores onto the plant.
• Symptoms don’t develop until the plant begins to reach maturity.
• Disease symptoms are favored by warm, humid conditions at plant maturity.
• Moisture at maturity plays a major role in disease development given the plant can be covered with pycnidia in wet years at maturity, whereas in dry years, pycnidia are confined to areas of the plant closer to the soil.

• Since the disease overwinters on infected crop residue, tillage and crop rotation will help reduce the infection. 
• An R3 to R6 fungicide application, such as Trivapro^®, can help mitigate disease and improve seed quality, but it is generally only recommended for soybean fields grown for seed. 
• For the year ahead, plant high-quality, pathogen-free seed for affected acres by choosing varieties resistant to pod and stem blight.