We finally have the right calendar date and soil temperature to plant, but are fighting the moisture across the CFS territory. Warm daytime air temperatures have pushed soil temperatures up rapidly, and fieldwork will commence as soon as conditions allow:

• 6” soil temperatures near Mankato increased from about 40-degrees on 4/15, up to a peak of 54-degrees on 4/22!
• Avoid the temptation to plant “on-the-wet-side.” Yield reductions resulting from "mudding the seed in" may be greater than those resulting from a slight planting delay.

Soybean Planting Considerations

As the calendar turns to May soon, we are confident soybean planting will be ramping up, but we can’t forecast what the weather will be like the weeks after we plant. The average temperature in southern MN hovers in the mid-60’s the 1^st week of May, but rainfall is always variable.

4 Factors to Minimize Disease Risk

Soybean seed and seedlings can be threatened by many diseases that are activated by soil temperature and moisture. We can’t forecast what the weather will be the first few weeks or what associated soybean seedling diseases will be prevalent, but there’s opportunities to minimize risk with adding seed treatments to your soybean seed. Seed treatments provide four main agronomic benefits:

• Optimize germination due to 2018 seed quality challenges
• Manage unknown weather & corresponding seedling diseases
• Offer protection against insects and nematodes
• Protect population from falling off the yield cliff

Optimize Germination

The large amounts of rain that occurred throughout August and September last fall increased the potential for seed decay and a mix of fungal pathogen infection. Seed decay can cause reduced seed vigor, germination and emergence. However, if soil conditions are wet and cool at planting, germination rates could be more affected than normal and impact the survival and soybean stand counts. Many university research articles point towards an increase in cold germination rates of 10-20% with the use of appropriate seed treatments. Adding a seed treatment can improve soybean seed quality and germination by controlling the fungal pathogens isolated from soybean in 2018.

Even if soybeans are planted in warmer temperatures later in the season, it doesn’t reduce the risk of seedling diseases. However, it does change the disease type spectrum. Seedling diseases like Rhizoctonia and Phytophthora are most active with warmer temperatures, while Pythium and Fusarium prefer cooler soil temperature with varying degrees of soil moisture saturation.
 

Manage Unknown Weather and Seedling Disease

Phytophthora is one of the most common MN seedling diseases, and results in damping-off and seed and root rot, along with stunting, plant death from emergence through R5, stand reduction and yield loss. Phytophthora is problematic in saturated, compact soils. Seed treatments with fungicide components that include metalaxyl as an active ingredient are often used to reduce Phytophthora infection. Seed treatments with mefenoxam, the active isomer of metalaxyl, are also a strong agronomic choice since the mefenoxam active ingredient can be more than twice as effective as metalaxyl alone.