Cause This is a physiological disorder. High fertility and high temperatures aggravate the disorder. Some research indicates it may be influenced by an imbalance of nitrogen, potassium, and calcium. Water stress followed by a period of excessive growth and low humidity favors development of tip burn. These conditions influence calcium uptake and distribution in the cabbage head. Amount and frequency of irrigation appear to influence incidence of tip burn. All cabbage varieties grown in Oregon are susceptible to some degree with some differences between varieties.
Symptoms A marginal necrosis of internal leaves. Symptoms can extend from a few small, brown spots on interior leaf edges to large areas of the leaf margin turning brown and eventually decaying. External symptoms usually are absent.
Cultural control No completely effective controls are known.
- Holding nitrogen levels as low as possible commensurate with adequate yields is helpful. Nitrogen rates should not exceed 100 lb/A. The form of nitrogen may be important; ammonium forms are less desirable than nitrate forms.
- Do not apply excessive rates of potash or other nutrients that would compete with calcium uptake.
- Soil samples should show adequate base saturation and adequate levels of calcium.
- Use adequate irrigation to avoid water stress conditions that would interfere with calcium movement to inner leaves.
- Harvest cabbage at optimum maturity to avoid it becoming excessively firm.
- Grow tolerant varieties. Research in New York rated varietial susceptibility as follows:Slightly susceptible cabbage varieties: Superdane, Falcon, Hinova, Atria, Rudolfo, Superkraut, Krautpaker.More susceptible cabbage varieties: Titanic 90, Roundup, Bravo, Krautking, Little Rock. Quite susceptible varieties: King Cole, Quisto, Superette.Very susceptible cabbage varieties: Green Boy, Rio Verde, Condor, Izalco.
Reference Rosen, J. 1990. Leaf tip burn in cauliflower as affected by cultivar, calcium sprays, and nitrogen nutrition. HortScience 25:660-663.