Hollow stem occurs in cauliflower, broccoli and cabbage. The thick, fleshy center of the stem core splits due to an uneven growth rate and an elongated cavity forms. The cavity may extend to either end of the plant to produce an opening to the outside environment. When this occurs, infections by fungi and bacteria are common.
Conditions for Disease Development
Irregular or sudden rapid growth, high temperatures, high nitrogen levels and low plant populations favor development of hollow stem. A boron-deficient growing condition may also encourage this disorder.
Avoid excessive soil fertility. Increase planting density for broccoli to help decrease plant growth rates and reduce the incidence of hollow stem.