Fusarium wilt is caused by a soil-borne fungus that can persist in fields for many years. Symptoms include wilting, yellowing, and leaf distortion. Single plants or clusters of plants may show symptoms. (Photo: Kenneth Seebold, UK)

Fusarium wilt generally affects one side of a tobacco plant. Leaves on the affected side are often curved to one side, with half the leaf yellowed and the other half remaining green. (Photo: Kenneth Seebold, UK)

Cutting through the stalk of a tobacco plant with Fusarium wilt will reveal a dark discoloration of the vascular tissue. (Photo: Kenneth Seebold, UK)