Reducing Stalk Rots and Lodging
Stalk rots cannot be entirely prevented but their effects can be reduced through good management practices. The following practices can help reduce stalk rot, lodging and harvest losses:
Hybrid differences. Hybrids vary in their resistance to leaf diseases, stalk rots, drought stress and stalk lodging. Pioneer Hi-Bred provides ratings for these traits. Growers should select high-yielding hybrids with good disease resistance, standability and stress resistance. Your Pioneer sales professional can help match the right hybrid to your fields and growing conditions.
Soil Fertility. Test soils regularly and apply nutrients based on soil test results and yield goals. Be sure potassium levels are adequate, and manage nitrogen to prevent losses and ensure its availability throughout plant uptake.
Crop stress. Crop stress is never eliminated but can be reduced with good crop, soil and water management. Excessive plant populations increase stress and stalk lodging. Poorly spaced or "clumped" plants create a high population microenvironment similar to overplanting. Maintain planter and planter meters properly and do not exceed manufacturer's suggested ground speed. Calibrate planter meters for optimum plant spacing and monitor rates carefully when planting. Compaction is one of the primary causes of crop stress, and may persist for several years. Avoiding compaction and maintaining soil quality are keys to reducing crop stress. Proper irrigation management is critical to minimizing crop stress in arid regions.
Insects. Manage insects such as corn borer and fall armyworm to prevent plant wounds and stress. Pioneer® brand hybrids with Herculex® XTRA insect protection provide in-plant protection from both of these pests, in addition to corn rootworm.
Corn Residue. Stalk rot pathogens overwinter in corn residue. Occurrence and intensity of stalk rots is sometimes related to the amount of inoculum present. A prime example is anthracnose which is prevalent in continuous corn and no-till fields. Rotation to a non-host crop such as soybeans is recommended to reduce corn residue and stalk rot. Disking or otherwise incorporating residue may also be beneficial in some fields. Reduction of stalk rots must be weighed against the advantages of soil conservation and maintaining soil carbon levels when deciding whether to till.
Scouting. Careful scouting and harvesting fields according to crop conditions can help prevent field losses due to stalk rot. Potential lodging and yield loss should be weighed just as heavily as grain moisture in deciding which fields to harvest first. Scouting fields approximately 2 to 3 weeks prior to the expected harvest date can identify those with weak stalks and predisposed to lodging. Consider harvesting those fields early. Weak stalks can be detected by pinching the stalk at the first or second elongated internode above the ground. If the stalk collapses, the plant is in an advanced stage of stalk rot. Another technique is to push the plant sideways about 8-12 inches at ear level. If the stalk crimps near the base or fails to return to the vertical position, stalk rot is indicated. Check 20 plants in five areas of the field. If more than 10-15% of the stalks are rotted, that field should be scheduled for early harvest.
Weak stalks can be detected by pinching the stalk at the first or second elongated internode above the ground. If the stalk collapses, the plant is in an advanced stage of stalk rot. Another technique is to push the plant sideways about 8-12 inches at ear level. If the stalk crimps near the base or fails to return to the vertical position, stalk rot is indicated. Check 20 plants in 5 areas of the field. If more than 10-15% of the stalks are rotted, that field should be scheduled for early harvest.
Checking for stalk rot.