The accompanying table describes many of the possible causes of white heads, and ways to differentiate those causes. Plant Disease Alert . White mold is a serious problem on dry beans, especially under irrigation. University of Minnesota trials at Staples, MN have demonstrated that proper irrigation management is very important. Producers can make these determinations on a field by field basis simply by using a rain gauge.
Reports indicate that some dry beans are flowering before the rows close.
These plants may dry out quicker, reducing white mold potential. However, plants could form a canopy quickly in warm, wet weather, increasing white mold risk. Fungicides to Use. Benlate and Topsin M are registered for white mold control on dry beans. One of the most economic and effective ways of using a fungicide is to use ground application with a directed spray, a modification of what is thought of as a band spray.