White Mold of Soybeans and Foliar Fungicides
With the wet
Before making a fungicide application, there are a few things to consider. Has there been a history of white mold in the field in question? Are weather conditions favorable for infection (cool and moist)? How susceptible is the variety you planted? Do you have high plant populations or narrow rows? All of these things can influence the amount of disease that develops.
Be realistic about the control that will be achieved with foliar fungicides – complete control is unrealistic. Fungicides are not a silver bullet for white mold management. In Michigan State University trials, we obtained 80 percent control of white mold in 2013; however, in 2014, with highly favorable weather conditions and heavy disease pressure, we only managed to control 9 percent of disease. Once disease symptoms are present in a crop, it is too late to save infected plants.
If fungicides are to be used, they should be applied at the beginning of flowering (R1) with a possible follow up application a week or two later, up until the beginning of pod development (R3). As the disease cycle is dependent on
If the decision to spray is made, it is advisable to keep replicated, non-sprayed check strips in representative areas of the field to see how the fungicide application performed under your conditions. This is important as low areas that hold moisture or where cool air pools will be at greater risk for developing
For more information, read “Management of White Mold in Soybean,” produced through the North Central Soybean Research Program.
Source: Martin Chilvers, Michigan State University Extension