TB - Tip Burn
Type: Physiological Disorder
Tip Burn is caused by inadequate transport of calcium to rapidly growing tissues. It has caused severe loses to growers in the United States and Europe. It affects Brussels sprouts, cabbage, cauliflower, kohlrabi, and lettuce. Uneven rainfall and watering, high temperatures, high humidity, windy conditions, dry soil conditions, and rapid growth are all factors. Tip burn consists of a breakdown of the plant tissue near the center of the head and develops as
the crop approaches maturity. The inner leaves of heads of cabbage are affected, often without external symptoms. The inner leaves turn dark brown, then to a black color. Symptoms can extend from a few small brown spots on interior leaf edges, to large areas of the leaf turning brown and eventually decaying. Secondary rot caused by bacteria can follow tip burn and heads of cauliflower can be severely affected. No completely effective controls are known, but excessive soil moisture and insufficient soil moisture have both been suspected as contributing to a calcium deficiency. Managing irrigation can regulate and control plant growth and calcium deficiency. The best option is to use varieties resistant to tip burn.