The Soybean Situation
According to the Badger CropDoc Wisconsin Soybean and Corn Disease update for August 2, 2021, officials observed and received reports of some fields with Phytophthora root and stem rot of soybean.
Damon Smith, Associate Professor and Extension Specialist and Field Crops Pathologist says he has fielded many questions on why is happening and whether growers are seeing changes in the races of the Phytophthora organism in Wisconsin. My short answer is probably not. However, we have found a new species of Phytophthora in some fields that can affect soybean, Smith said in his Badger CropDoc blog.
The new species, Phytophthora sansomeana, can be found in mixed infections with P. sojae.