Main Symptoms
 

One to several leaves on infected plants turn yellow and dry up, usually on one side of the plant (figures 1 and 2).

A longitudinal section of  the vessels reveals a homogeneous chocolate brown color (figures 3 and 4).

Occasionally young leaves and the bud area may be distorted.

Some of the information on the disease distribution worldwide is obtained from surveys conducted by CORESTA (Cooperation Centre for Scientific Research Relative to Tobacco). The reliability of the information has not been confirmed in all countries.

U.S. situation

Fusarium wilt is most frequently confused with bacterial wilt. The two diseases may look very similar at first because both cause wilting of a few leaves or on the one side of the plant. Examination of the stalk underneath the outer bark is the most reliable way to distiquish the two diseases. If the color is chocolate brown it indicates  fusarium wilt. If black streaks are observed it is likely Bacterial wilt.

A practical tip: with fusarium wilt the outer bark should “peele” easily from the rest of the stalk. With bacterial wilt it is impossible to remove the outer bark from the rest of the stalk.

(Mina Mila - North Carolina State University)