Recent rains have created conditions conducive to disease development on corn and soybeans according to Jill Scheidt, an agronomy specialist with University of Missouri Extension in Barton County.
"Rain carries funguses in the air which makes it easier for the funguses to spread. Diseases like rust, gray leaf spot, northern corn leaf blight, brown spot, crazy top and stalk and ear rots develop best in wet and humid conditions," said Scheidt.
Fungicides that effectively and economically suppress these diseases are most effective if applied while corn is in the vegetative stage, or before silking. If corn already has silks, plants will not respond as well to a treatment.
"It is not economical to apply a fungicide past the tasseling stage," said Scheidt.
SDS can be a problem with wet conditions
Sudden Death Syndrome or SDS may become a concern with wet conditions after planting and later in the season during bloom. According to Scheidt, wet conditions early in the season are conducive to the infection of SDS and wet conditions during bloom or late in the season are conducive to symptoms being expressed.
"It is difficult to assess yield loss due to SDS. Yield loss is more likely if leaf tissue dies and pods or blooms are aborted rather than seeing severe yellowing between the veins," said Scheidt.
Other foliage diseases that affect soybeans during wet conditions are septoria brown spot, downy mildew and bacterial blight. Young plants that are in flooded or saturated soils have an increased chance of root rot diseases.