Sorghum Downy Mildew
Symptoms:
- Leaves have yellow to white stripes extending from the base of the leaf toward the leaf tip
- Infected leaves often will be more narrow than usual, erect, and shredded
- A white, downy mycelium may develop on both surfaces of leaves
- Plants may be stunted, chlorotic, and have an irregular seed set
- Symptoms vary according to plant tolerance
Pathogen Involved:
- Peronosclerospora sorghi (a fungal-like pathogen)
- Pathogen is located worldwide and causes a systemic infection
- Overwinters in the soil
Time of Occurrence:
- Occurs before mid-whorl
Conditions Favoring Disease:
- High humidity or free water
- Warm temperatures of 70 - 80°F
Disease Management:
- Use resistant hybrids
- Plant in cool soils
- Avoid rotation of corn with sorghum and adjacent planting of corn and sorghum
- Destroy shattercane, because it is an alternate host for the pathogen
- Systemic fungicide seed treatments may be helpful