Fungicide applications in a delayed planting season

Fungicide applications in a delayed planting season

Fungicide applications can regularly be a tough choice for growers in a marketplace with such slim margins but this year’s delayed planting will likely make it even worse. Work through the following items with your Jacobsen Seed Representative to figure out if fungicide application is best for your farms this season.

Fungicide is best when it fights a disease 

While there are many plant health benefits that come with fungicide applications, the biggest return on investment comes from fighting disease. Begin by understanding what hybrids are listed as susceptible or average against foliar diseases such as Gray Leaf Spot and Northern Corn Leaf Blight and scout those fields first and most often. There is little to no genetic protection for our RM zones in soybeans for diseases such as Frogeye Leaf Spot and Septoria Brown Spot so all fields should be scouted equally. Work with your Jacobsen Seed Representative to understand economic thresholds for each disease and how to react accordingly.

Fungicide protects yield potential, it doesn’t create it.

 Fungicides are great at protecting crops from yield robbing diseases. They can’t create additional yield potential in a field that has been limited by other factors. Fields of both corn and soybeans that have been

  • severely delayed in planting
  • waterlogged
  • face sidewall compaction
  • can visually see nutrient stress
  • face weed competition

are likely not good candidates for fungicide application. Look at each field’s yield potential and insurance implications separately before making a fungicide application.

Weather and timing are against us

For those fields that still are looking good and have few yield limiting factors, the weather and timing of crop stage are working against us. Many fungal pathogens in corn and soybeans thrive in damp and humid conditions, like much of the weather we have faced so far this season. This could lead to a higher incidence of disease compared to normal. If diseases show up, it is also possible they will be infecting the crop at an earlier developmental stage than normal. Studies have shown that the earlier a pathogen infects a plant, the more serious the yield loss can be. Earlier infection means that the grain fill period is more likely to be impacted by loss of plant tissue. This leads to reduced sugar production and therefore less dry matter put into grain. Begin scouting early. The biggest return on investment consistently comes from fungicide applications made at VT/R1 (tassel/silking).

 Use resistance management strategies

Just like in weed management, disease management plans need to be cautious about the development of resistant crop pests. This is especially true in soybeans. Recent studies of Frogeye Leaf Spot have shown widespread resistance to strobilurin (Group 11) fungicides. Talk with your chemical provider about using products with multiple active ingredients and modes of action. This will help control resistant pathogens as well as slow the development of new resistance.