Pioneer Agronomist: Wet Conditions Can Increase Southern Soybean Seedling Disease Risks

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If the forecast calls for rain, it could bring much needed moisture to soybean seedlings. It can also increase the likelihood certain pathogens will attack vulnerable soybean seeds and seedlings. When wet conditions are prevalent, growers in southern states should be on the lookout for early-season diseases, such as Phytophthora, Pythium, Rhizoctonia and Fusarium, which survive in diseased plant material and in the soil.

“Going out to your fields and looking for damping off is easy. What isn’t always easy is determining which pathogen caused the damping off,” said Suzannah Wiggins, Pioneer Field Agronomist in Tennessee and Kentucky. “To better determine the cause of seedling injury, dig up and analyze a few seedlings. Taking into account soil temperature at planting and moisture levels can help rule out some disease options.”

Pythium and Fusarium are more likely to occur when soil temperatures are less than 59°F. Phytophthora and Rhizoctonia are commonly found when soils are between 68°F and 81°F.

Growers can reduce seedling disease risk using sound planting practices that minimize stress, as well as with fungicide seed treatments. Adding an insecticide to the treatment provides an additional layer of protection, helping prevent insect feeding, which is a common entry port for pathogens.