Once a field dries enough for cultivation, this may be used to help dry and aerate the soil. It will not stop established infections but may help reduce new infections. Phytophthora Root Rot of Soybean. This disease is favored by warm wet soils. Some varieties are resistant to the most common races in the area, but not to all races present.
Plants turn yellow green and wilt.
Often a dark streak can be seen above the soil line on the stem of susceptible varieties. This streak may extend up to the second or third node. As with Aphanomyces, cultivation to help aerate and dry the soil may help reduce new infections, but will not stop established infections. Downy Mildew of Sunflower. This is discussed in a separate article.