Ethanol has dramatically increased the demand and the price of corn in 2006. This has resulted in an expected increased corn acres with fewer alternative crops in the rotation. In many cases the most profitable rotation is continuous corn. In addition, the increased fuel costs and improvements in machinery, seed, and seed treatments have encouraged a shift to reduced tillage, including no-till. Both continuous corn and no-till can have dramatic effect on plant diseases.

No-till soils tend to be cooler and wetter at planting and Pythium seedling decay and root rot can become a major factor. Pythium seedling decay and root rot is caused by an Oomycete (closely related to brown algae) and is considered a “killer” that can reduce plant populations substantially. Unlike soybeans that can compensate for missing plants, corn yields are dependant upon uniform populations. In continuous no-till corn, two other soil-borne diseases flourish. They are Fusarium root rot and Rhizoctonia root rot, which are considered “nibblers”, because they generally reduce the root mass, especially the small fine roots. When plants are under moisture stress, they lack of these root hairs reduce the plants ability to extract water from the soil and can reduce yields without killing the plant.