Several celery samples from high tunnel production with leaf curl have been identified by the UNH Plant Diagnostic Lab, and leaf curls on celery plants were also observed during a farm visit in in summer 2023. Celery is an important vegetable in the United States. Celery leaf curl or celery anthracnose was first observed in the U.S. in 2012; this disease causes significant economic losses in celery production.
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Fig. 1. Celery with anthracnose showing leaf curl symptom.
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Fig. 1. Celery with anthracnose showing leaf curl symptom.
Symptom
Celery anthracnose is characterized with typical leaf curl symptom (Fig. 1), occasionally with discoloration of leaf margins, twisted petioles, and lesions on petioles (Fig. 2). The symptoms are similar to herbicide damage and physiological disorder with calcium deficiency. However, the leaf curl caused by anthracnose is usually downward cupping, whereas the herbicide damage can result in upward cupping.
Fig. 2. Celery with anthracnose showing brown lesions on stalk.
Causal agent
The fungi that cause celery anthracnose are Colletotrichum fioriniae and C. nyphaeae. C. fioriniae mainly cause leaf curl symptoms. C. fioriniae also causes bitter rot of apples, and C. nymphaeae causes anthracnose of strawberries.
Life cycle
Anthracnose pathogens are seed borne, which can survive in infected plant debris. These pathogens infect several weeds, including common lambsquarters, redroot pigweed, yellow nutsedge, oakleaf goosefoot, and common groundsel. Spores are spread primarily by splashing rain or irrigation water. Warm and wet conditions stimulate infection and disease development. Rapid disease development occurs at 77 – 86 ºF; long wet periods of 48 – 96 hours best promote outbreaks. Celery anthracnose frequently develops when it has been very hot with heavy thunderstorms followed by high humidity.
- Celery seed can be treated with hot water to kill pathogens on the surface and within the seed.
- Clean transplant trays.
- Scout greenhouses and fields regularly. Rogue out suspect plants and destroy.
- Avoid overhead irrigation. Use mulch to minimize splashing of field soil onto plants.
- Remove host weeds to improve air movement.
- Avoid working with crops during wet weather.
- Rotate no-host crops with celery for 3 - 4 years.
- Use resistant cultivars, such as Merengo, Hadrian, Geronimo, and Balada.
- Apply fungicides such as strobilurin (FRAC Group 11). For the current labeled fungicides, please see the New England Vegetable Management Guide.
