Soybean Disease

Flooding injury occurs when soils are saturated for several days and anoxia develops.  The roots are killed, as are the nodules that are home to the nitrogen fixing bacteria. The field has an “interesting’ smell but the key symptoms of this injury are on the roots. Dig up a few plants – if it is flooding injury the outside of the root – the epidermis will be easily pulled off the root leaving the white center – looks like rat tails (Figure 1). In addition, the nodules will be gray and easily crushed.

Several reports over the last two weeks of heavy frogeye leaf spot pressure in some fields as well as low to moderate pressure in others.  This disease will continue to increase and infect new foliage as it develops on these late planted soybeans. Based on our previous research, only once (2018) in 14 years of studies did applications at the soybean growth stage R5 contribute to preserved yield.  At the R5, the leaf at the terminal is fully developed and the pods at any one of the top four nodes is fully expanded, but the seeds are just beginning to expand.