White Mold isn’t a problem every year but when it does hit it can be very substantial to yield in soybeans. A good example would be 2009. In fact, in 2009 a white mold research study conducted by the University of Illinois showed a yield loss of 43% with disease levels of 75 to 95%. That is why we bring this up, because a lot of the fields that had white mold in 2009 are soybeans again this year.
What types of environmental conditions favor White Mold?
Wet weather
Cool Temperatures
High humidity
Moist soil
Bloom and early pod fill are prime conditions for white mold to infect the plant. The disease often develops in areas where extended periods of dew or fog are present.
Is narrow row spacing correlated with higher levels of White Mold?
Anything that favors earlier canopy closure and shading of the soil surface will restrict air movement, increase dew periods and cool the soil surface. Therefore early planting, narrow row spacing and high plant populations all favor disease development.
When should an application be made?
Take action before signs of infection occur. Application should be made between V5 (five leaf nodes) and R3 (early pod development) with the optimum timing at R1 (early flowering). The longer you wait to spray after first flower the less effective an application will be.
