The first symptoms of Fusarium wilt occur on older leaves that change color to dull green and yellow. Leaves can become dry, brittle and dark brown and die. Early in the stage of disease, plants wilt early in the day, but recover in the evening. As infection advances, wilting becomes permanent. The vascular tissue often appears brown as it becomes infected and water transportation from the roots to the foliage is reduced, causing plant wilting.
In young seedlings and plants, Fusarium can cause damping off (pre- and post-emergence) and stem collapse. Symptoms on older plants include yellowing, stunting and wilting. Fusarium can cause plant death at any growth stage, but older plants are more tolerant to infection than younger plants. Characteristic symptoms of Fusarium wilt include browning of vascular tissue in the crown and tap root.
"The Fusarium wilt fungus infects plants through the rootlets, invading the xylem and eventually extending throughout the plant. Individual branches and associated leaves on plants infected with Fusarium become yellow and wilt. Sometimes only one branch or one side of the plant is affected, creating a yellow flag effect. Infected plants usually die. A dark brown vascular discoloration extends far up the stem. Symptoms often first appear during fruit sizing." (B. W. Falk, 2014)
Recommended controls for fusarium wilt
Each control will have its own set of parameters that will be best suited for individual environments. Certain controls may only be available for commercial application.
Commercial farmers are required to reference their own state laws to ascertain if the recommended controls fall within compliance of their states regulatory guidelines.
Cultural, MECHANICAL AND PHYSICAL CONTROLS
- Provide proper sanitation and cultural care to reduce plant susceptibility to infection and damage.
- Avoid overwatering and provide good drainage.
- Avoid applying excessive fertilizer.
- Soil solarization before planting may be effective.