Integrated Crop Management is published by the Department of Entomology , Iowa State University , Ames, Iowa. Increased risks associated with late planting occur because plants are at an earlier growth stage at the onset of disease.
Plants infected earlier in their development suffer greater yield reductions.
It can pay to be aware of how specific diseases are affected by planting date. In soybeans, root diseases such as Phytophthora, Rhizoctonia, and sudden death syndrome can strike any time during the season, but the risk of infection is greater if soybeans are planted early into cooler, wetter soils. Timely cultivation can help dry the soil, reducing the risk of root rots and promoting root development. Care must be taken not to damage the roots during cultivation. In oats, the two major diseases, barley yellow dwarf virus and crown rust, become active in late May and early June.