Minnesota crop disease concerns 2024

By Scout Nelson

Excessive rain in Minnesota's crop fields this year may lead to increased problems for corn and soybean growers. Issues such as nitrogen loss, poor root development, and plant stunting can arise even without disease presence.

However, wet soils also create ideal conditions for various diseases to thrive, potentially damaging plant roots and stems.

Root Diseases:

Root rots are favored by wet soil and are more common in soybeans than corn, though both crops can be affected. Diseases like Phytophthora root and stem rot and Rhizoctonia root rot are currently occurring in warm, moist soils.

Seed treatments and resistant soybean varieties can help manage these diseases. Scouting and accurate identification are essential for understanding the extent of these problems and planning future management tactics.

Soybean SDS and White Mold:

Wet early-season conditions increase the risk of sudden death syndrome (SDS) and white mold in soybeans. SDS thrives in periodic rains and moist soils during mid to late summer, while white mold prefers cool, wet weather from early July to mid-August.

If dry weather returns in early July, the risk of these diseases decreases. White mold can be managed with specific foliar fungicides applied at the R2 or late R1 growth stages.

Leaf Diseases:

Leaf diseases like northern leaf blight, Physoderma brown spot, and tar spot in corn, and bacterial blight, frogeye leaf spot, Septoria brown spot, and Cercospora leaf blight in soybeans, are favored by wet or humid weather.

These pathogens overwinter on crop residue, and continued wet soil enhances their growth and spore production. Although early-season foliar fungicides are not generally recommended, applications at the R3 stage for soybeans and VT-R1 stage for corn are most cost-effective.

The wet weather may set up significant disease problems in some fields, especially if conditions remain favorable for diseases in July and August. While most fields may not experience major issues, it is crucial to remain vigilant.

Scouting and proactive disease management are essential for minimizing potential yield losses due to increased disease risk in Minnesota’s corn and soybean crops this year.

Photo Credit: gettyimages-studio2013