Cause A deficiency of boron in the plant.
Symptoms A transverse cracking of the epidermis sometimes occurs over the entire mature petiole. Epidermal layers turn a brownish black, and tissue immediately beneath turns brown. This characteristic symptom may be accompanied by leaf mottling, root browning and dying, brittleness, and some brown, shallow, longitudinal streaking of the fleshy petiole.
- Ensure adequate soil boron levels particularly in sandy and alkaline soils. Depending on soil test, add 1 to 5 lb/A actual boron to fertilizer.
- At the first sign of cracked stem, spray soluble boron at 1 lb/100 gal in a volume of 100 to 150 gal/A.
Reference Kendrick, J.B., Wedding, R.T., Middleton, J.T., and Hall, J.B. 1954. Some factors affecting development and control of adaxial crack stem of celery. Phytopathology 44:145-147.