Reports of White Mold – Soybean Too Late to Spray

We are starting to receive reports of white mold in soybean. With the exception of later planted soybean, most of the soybean crop is at the R4 into R5 growth stage. As you scout the soybean crop, areas of wilted soybean plants may be indicative of white mold (Figure 1). Closer inspection of the wilted area will often lead to the “white mold” symptom that is diagnostic, which is the fluffy white mycelium (Figure 2). Seeing symptoms of white mold means that the plants were infected weeks earlier and the application of a foliar fungicide for control of white mold is not recommended. Also, as earlier stated, with most of the soybean crop past the R3 growth stage, foliar fungicides are not recommended even if scouting does not show evidence of white mold.

For further information about scouting for white mold, please consult:

White Mold of Soybean in Wisconsin

and

White Mold in Soybeans

Figure 1. Areas of soybean where plants are wilted. This is often indicative of white mold.

Figure 2. White mycelium on the soybean stem are a good diagnostic indicator of white mold.