Diplodia Stalk Rot
Symptoms of Diplodia Stalk Rot
- Symptom:
- Diplodia stalk rot may first be evident when affected plants die suddenly during mid- to late-ear fill.
- Upon examination, dark brown lesions can be found extending in either direction from the node.
- Small black spots (pycnidia) may develop just beneath the stalk epidermis near the nodes. The black dots are not easily removed, which distinguishes Diplodia from Gibberella.
- Diplodia results in rotted stalks that are disintegrated and discolored (brown), allowing the stalk to be crushed or easily broken.
- Although the pith disintegrates, vascular bundles remain intact
- Diplodia Stalk Rot Facts:
- Caused by Stenocarpella maydis fungus (formerly called Diplodia maydis)
- Corn is the only host of this pathogen
- Survives on corn stalk residues
- Spores are spread by wind or splashing rain
- Favored by warm, wet weather two to three weeks after pollination
- Management:
- Genetic resistance – choose hybrids with high scores for stalk strength
- Crop rotation – at least one year out of corn
- Tillage to help break down crop residue
- Maintain balanced fertility
- Use moderate plant population if field has a history of stalk rot or lodging
- Reduce plant stress if possible
- Control stalk-boring insects to prevent wounds stalk rot organisms can enter.
- Pioneer® brand hybrids with Herculex® I or Herculex Xtra Insect Protection traits give excellent control of European and southwestern corn borer.
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