Host: burley tobacco (Nicotiana tabacum (burley type)
Description: Symptoms of the brown spot fungus first appear on the lower leaves. Spots are brown with sharply defined margins and may be surrounded by yellow halos. The primary distinguishing characteristics of brown spot are the dark concentric rings within spots that give it a target-like appearance. With magnification, reproductive structures of the casual agent are seen as tufts of black fungal spores (conidia). Under severe conditions, spots are numerous, may coalesce, and give the leaf a ragged appearance as the infected tissue falls out.
Image type: Field
Image location: United States
Name: R.J. Reynolds Tobacco Company Slide Set
Organization: R.J. Reynolds Tobacco Company
Country: United States