How to prevent and control non-infectious diseases in clivia?

So-called non-infectious diseases are actually a kind of physiological disease that has not been attacked by living organisms. They include ecological and environmental conditions unsuitable for the normal life of clivia. For example, if the salt content in soil and water is high, and the concentration of soluble salts is higher than the level clivia can tolerate, salt damage will occur, leading to a series of factors such as disrupted water supply, deficiency of nutrient elements, unsuitable temperature and light, improper cultivation and management, and the invasion of other harmful toxic substances, producing injuries, freezing damage, chemical damage, and so on. All these pathological conditions affecting the normal growth and development of clivia are collectively called non-infectious diseases.

1. Sunscald

Also called sunburn. It is a physiological disease, mostly occurring in summer and autumn. It is caused by high temperatures in the growing environment and strong light shining directly onto the leaf surface. In mild cases, the leaves turn from green to yellow; in severe cases, the leaves dehydrate, dry up and die.

Occurrence pattern: Unclear yellow dry patches appear at the edges of affected leaves. This disease seriously affects the ornamental value and normal growth and development of the plant, thereby reducing the quality of the plant.

Prevention and control methods: (1) When growing clivia in a greenhouse, appropriate shading should be provided from June to September. When the indoor temperature exceeds 30°C, ventilation should be strengthened or water spraying should be used to lower the temperature. (2) When growing clivia at home, strong direct light and high temperatures should be avoided, and it should be placed in a shady place. (3) Once sunscald occurs in clivia, the damaged leaves should be cut off to prevent other diseases.

In summer and autumn, with high temperatures and strong light, attention should be paid to avoiding light. The flower cellar can be fitted with shade nets, bamboo blinds, reed blinds, etc. to reduce light intensity, create an environment with scattered light, and pay attention to ventilation and cooling.

2. Chlorosis

Also called lack-of-green disease. Clivia chlorosis is caused by acute water shortage and iron deficiency.

Occurrence pattern: Affected leaves show milky white patches, or all become yellow-white; in severe cases they wilt, wrinkle and wither. Clivia chlorosis has many manifestations: leaves all turning yellow is often a symptom of sunscald. Leaves beginning to turn yellow from the tip are often caused by cultivation soil not being fully decomposed, or by excessive fertilizer and water, causing root burn. Individual leaves turning yellow is very likely the result of fire scorching, cold wind attack, or acid-base erosion. Sometimes the leaves of the whole clivia plant turn yellow, mostly because of a nutrient deficiency disease. Another kind of leaf yellowing is caused by insufficient light.

Prevention methods: In summer, place clivia in a shade shed, a cool and ventilated location, and expose clivia to light with 50% shading to prevent sunscald. Clivia must be cultivated with decomposed, loose, slightly acidic leaf mold soil. When the temperature exceeds 30°C, fertilizer should be applied sparingly or not at all, and the amount of watering should be reduced accordingly to prevent leaf yellowing after root rot. If yellowing occurs because of a lack of nitrogen fertilizer, the grower can appropriately increase the application of cake fertilizer. At the same time, a 0.1-0.2% ferrous sulfate aqueous solution can also be sprayed on the leaves every day. In winter, strengthen lighting; it is best to give clivia a sunbath at a fixed time every day. Through such observation and management, clivia rarely develops chlorosis.