Deficiency Diseases and Symptoms

Table 12.2 groups mineral deficiency symptoms by the name of the disease or symptom they produce and lists which minerals are responsible for each. Some symptoms, like chlorosis and necrosis, are caused by several different minerals and have to be told apart by exactly where on the leaf they appear: interveinal chlorosis (yellowing between the veins while the veins stay green) is caused by magnesium, iron, manganese or zinc deficiency, while marginal chlorosis (yellowing at the leaf edge) is specifically a potassium symptom. Necrosis, the death of tissue, is caused by deficiency of magnesium, potassium, calcium, zinc, molybdenum or copper. Several deficiencies are named after the specific disease-like appearance they cause in a named crop rather than by a generic symptom: copper deficiency causes die-back of shoots, reclamation disease in cereals and legumes, and exanthema (gum exudation from the bark) in citrus; calcium deficiency causes hooked leaf tip; zinc deficiency causes little leaf; boron deficiency causes brown heart of turnip and internal cork of apple; and molybdenum deficiency causes whiptail of cauliflower and cabbage. Stunted growth is a broad symptom of nitrogen, phosphorus, calcium, potassium or sulphur deficiency, anthocyanin (purple pigment) …