Got black spots on your roses, purple spots and yellow leaves on your photinia and Indian hawthorn, brown patch in your St. Augustine grass, damping off in newly planted seedlings or algae in your pond or water feature? You don’t have to use toxic chemicals like the synthetic fungicides such as Daconil or Bayleton or heavy metal products like copper sulfate. There’s a terrific natural solution to these problems. Cornmeal – and it’s available from the garden centers and feed stores.
Source : Cornmeal Uses and Reports