Diplodia Stalk Rot
Symptoms
- Symptoms may be similar to those of Gibberella stalk rot, but Diplodia doesn't develop pink color. White mycelium can develop in lower stalks.
- Tiny black specks (pycnidia) embedded in rind of lower stalk
- Lower, inner stalk may have shredded tissue and small, dark specks (pycnidia)
Pathogen Involved
- Stenocarpella (Diplodia) maydis (a fungus)
- Corn is the only host of this pathogen
- This pathogen overwinters on corn debris
Time of Occurrence
- Usually occurs after pollination
- The crown, mesocotyl, or roots are often the point of infection, however, the nodes between the crown and the ear can also be infected.
Conditions Favoring Disease
- Warm and wet weather
- Corn on corn rotation
- Stress from other diseases or insect injury
- Conservation tillage
Disease Management
- Use commercial corn hybrids that are resistant to Gibberella stalk rot
- Maintain balanced fertility
- Use the proper plant population
- Reduce plant stress
- Control stalk-boring insects