Soybean Disease

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.

Soybeans across the state range from ready to harvest to still flowering.  But in some fields, the yellowing was limited to pockets - some was sudden death syndrome or brown stem rot, charcoal rot, Phytophthora stem rot, and soybean cyst nematode.  There are some other early yellowing situations that we are still working on an accurate diagnosis, but yellowing in these cases may be linked to fertility issues and/or related to late flooding injury.  I think in 2018 we’ve observed just about everything, and it was all dependent on where in the state the soybeans were grown, how much rain occu