Host: flue-cured tobacco (Nicotiana tabacum (flue-cured type)
f.sp. nicotianae (Johnson) W.C. Snyder & H.N. Hansen
Description: This fungal disease causes slow yellowing and drying of the leaves. Symptoms are usually more pronounced on one side of the plant. Leaves may not wilt at first, but those on affected sides of the plants are usually stunted. The top of the plant may be drawn toward the diseased side. Wilting eventually occurs and upper leaves have a bronze cast. On the affected side of the plant, wood beneath the outer bark has a uniform chocolate brown discoloration. Such discoloration can also be seen in the midribs of affected leaves and in roots. Some roots on the affected side die. The unilateral appearance of symptoms and vascular discoloration can cause confusion between Fusarium wilt and Granville wilt. However, the "bacterial streaming" described for Granville wilt is a reliable way to distinguish between these two diseases. Fusarium wilt is frequently accompanied by root-knot nematode infection.
Image type: Field
Image location: United States
Name: R.J. Reynolds Tobacco Company Slide Set
Organization: R.J. Reynolds Tobacco Company
Country: United States