Powdery Mildew
Symptoms:
- All aerial plant parts can be infected, and infected areas typically appear as if white flour has been spread unevenly onto the plant surfaces.
- Symptoms are easiest to see on leaves, and may vary among cultivars to include yellow patches and defoliation.
- This disease is sporadic but is a common diseases on soybean plants grown in greenhouses for research.
Pathogen Involved:
- Microsphaera diffusa (a fungus). Other hosts include common bean, pea, and cowpea.
Time of Occurrence:
- Midsummer, after pollination.
Conditions Favoring Disease:
- Cool weather (66-74°F) is most favorable.
- Rainfall and humidity are not known to impact the disease.
Disease Management:
- Plant resistant varieties.
- Foliar fungicides may not be economically beneficial.