Fusarium Yellows of Celery

Fusarium yellows, also known as stunting, is the most important soilborne disease of celery crops. Originally, the disease was limited to self-blanching cultivars and was controlled by the planting of resistant green cultivars. The disease reappeared in 1959 as a new race (Race 2) that attacks both celery types.  Although Race 2 tolerant cultivars are available, the disease continues to be a production problem causing serious losses by affecting both quality and yield.

Fusarium yellows, caused by Fusarium oxysporum f.sp. apii, appears as an overall stunting followed by leaf yellowing. Vascular conducting tissue in roots and crowns is discolored brown. The central pith of the crown and root break down and are colonized by secondary decay organisms. The pathogen may infect large roots and cause them to become water-soaked and brown. Severely infected plants can collapse and die. Petioles on diseased plants may develop a bitter taste.

F. oxysporum f.sp. apii persists in the soil indefinitely. The pathogen survives in crop debris or soil as chlamydospores or as a saprophyte on other host plants or weeds. It is introduced into uninfested fields on transplants or as infested soil on farm equipment. Fusarium yellows are favored by dry soils and warm temperatures. Infection occurs through numerous sites in roots and disease development is influenced by soil temperature, pathogen population, and host susceptibility.

Management:

• Plant resistant or tolerant cultivars.
• Do not plant in fields with a history of Fusarium yellows.
• Prevent the introduction of the pathogen into uninfested fields by sanitizing farm equipment and starting with pathogen-free soil or potting mixes.
• Crop rotation is of limited effectiveness due to the pathogen’s persistence in the soil.
• Use of rock salt and chitin amendments are promising.