Because sclerotia survive for up to ten years in the soil, rotation is only a partial solution Weed Control White mold has over 400 plant hosts, including many broadleaf weeds. Host weeds that are also common weed species throughout soybean growing areas include lambsquarter, ragweed, pigweed and velvetleaf. In addition to acting as host to the disease, weeds can also increase canopy density, which favors disease spread. Chemical Applications Two fungicides, Benylate and TopsinM are registered as foliar fungicides for soybeans and are effective in reducing infection by white mold. However, proper timing of application and penetration of the fungicide through the soybean canopy are critical for success.
Pathologists recommend to apply when soybeans are producing flowers on the lower half of the plant.
Drop nozzles may be helpful to ensure spray coverage of those flowers. Pathologists suggest that fungicide application may be more practical for seed beans than for commercial fields. Researchers have begun to investigate the effects of post-emergence herbicide applications to control white mold. Preliminary studies have shown reduced white mold incidence and increased soybean yield by one application of Cobra at the V4 or R1 growth stage. These investigations are continuing.