Answers are from the Indiana certified crop adviser panel: Gene Flaningam, Flaningam Ag Consulting, Vincennes; Carl Joern, Pioneer, Lafayette; and Greg Kneubuhler, G&K Concepts, Fort Wayne.

 

A neighboring farmer makes multiple fungicide passes in his soybeans to keep white mold at bay. When should I make a fungicide application in my soybeans for white mold? What about other diseases? And should I apply a fungicide even if I don’t see disease problems?

 

Flaningam: White mold in soybeans is not prevalent in southwest Indiana. General fungicide treatment at R1 stage would be the time for a fungicide application. Look at cultural practices such as using 30-inch rows to let more air into the canopy. Crop rotations can also help considerably. Review soybean varieties for white mold resistance. There is always some variation between varieties.

 

Joern: Scout! White mold requires multiple fungicide applications to prevent it. The white mold pathogen needs decaying plant tissue, like senescing blossoms, as its infection site. Around the R1/R2 growth stage, the canopy begins to close, creating a humid microclimate — an ideal environment for infection. Conditions like cooler temperatures, excessive leaf wetness and poor air circulation also create the perfect environment for white mold to thrive.

 

If those conditions are forecast and you have white mold in your region, it’s time to make a fungicide application. The industry standard for white mold protection has been two passes of Aproach, with a two-week interval between applications. A new product, Viatude, contains a second mode of action to help fight this virulent disease. As with any fungicide decision, it’s important to be a good steward of these tools to preserve their effectiveness against the diseases we face.

 

I would advise against making a fungicide application in soybeans if a disease is not present. However, if you’re looking for a plant health benefit rather than disease control, there’s an expanding market for biostimulant products designed to regulate plant hormone expression. Consult with your trusted adviser on which products have been successful in your area for this specific goal.

 

Kneubuhler: To manage white mold in soybeans, the best measures include crop rotation, selecting more white mold-tolerant varieties and reduced tillage. If history suggests it’s there and you’re trying to eliminate the risk, fungicide applications during the susceptible flowering stage of R1 to R3 can help. That’s when conditions are favorable for the disease. If cool, wet and humid conditions persist, a second application about two weeks after the first may be beneficial.

 

Look for fungicides that are labeled for white mold or suppression — there are several in the marketplace. These products will also work against other diseases, so you can essentially kill two birds with one stone. The best use of any fungicide is to treat before there is a problem. Once disease shows up, fungicide applications then are essentially too late.