Causal Agent
Physiological Disorder
Distribution
Worldwide
Symptoms
Symptoms manifest as brown to black necrotic tissue at leaf tips. Leaves surrounding the growing point are particularly susceptible to this disorder. Tipburn is readily seen when exposed plant structures, such as leaves and curds, are affected. However, damage to the heads of Brussels sprouts, cabbage and Chinese cabbage may go undetected until they are cut open. In severe cases of tipburn, the head is soft and the plant is dwarfed.
Conditions for Disease Development
Tipburn is related to calcium defi ciency in developing tissues. Fast growth and high relative humidity favor symptom development. Developing leaves, which are already low in calcium, are severely stressed for calcium during times of rapid growth. Transpiration and translocation are slowed when relative humidity is high, thus calcium transport is inhibited.
Control
Grow tolerant varieties. Avoid excessive fertilization, and increase available calcium in the soil through soil amendments. Apply foliar nutrient solutions of calcium salts. Manage irrigation to help regulate plant growth.
中国
