Disease Resistance/Tolerance
It is important to match your disease package with the specific pathogens present on your farm. For example, continuous corn can result in increased levels of disease inoculums requiring hybrids with tolerance or resistance to certain pathogens. In addition, cooler wetter soils from increased residue can contribute to higher disease incidence. Implement an IPM program to determine what disease protection is important for your specific area. In addition, pay attention to University, agri-business, and private sector crop reporting services to monitor disease levels prevalent in your area.
Foliar Fungicides
In general, the use of foliar fungicides is recommended when foliar disease pressure is expected to be high. Conditions that favor foliar diseases in corn include continuous corn, no-till conditions and susceptible hybrids. If corn does not follow corn, fields are tilled, and/or hybrids have tolerance to disease, then fungicides are less likely to provide a benefit.
Corn following corn increases the risk of foliar diseases, especially under no-till conditions. Inoculum surviving on corn residue from the previous crop spreads to the subsequent corn crop, resulting in higher spore loads. If corn follows corn in no-till conditions and the hybrids are susceptible to foliar diseases, then a foliar fungicide is warranted.
Field location is an important factor in the use of foliar fungicides on corn. Fields in low-lying areas that experience extended periods of dew or fog create conditions favorable for foliar diseases, regardless of crop rotation. In these environments, fields with a history of foliar diseases are candidates for foliar fungicide applications.
Tillage often reduces the risk of foliar diseases. Tillage promotes the breakdown of previous crop residue that can harbor sources of inoculum for many foliar diseases. Field location and hybrid susceptibility also must be considered when determining to apply foliar fungicides. (provide a link to ladder).
For more information on this or other topics related to corn production, contact your state extension corn specialist or your local extension educator/agent.
The following is the link to the corn extension specialists: state extension corn specialist
