Reason: the growth of toon needs sufficient water, if the water is too little, the root system will not be able to effectively supply the tree with water, resulting in leaf transpiration is greater than the root system water supply, the phenomenon of yellowing will occur.

Treatment: late watering, good shade, pruning branches with leaves.

2, too little fertilizer

Reason: the growth process requires certain nutrients to help growth. If the soil is too poor, in the maintenance of the time did not timely fertilizer, it will also be due to malnutrition and the problem of yellowing leaves.

Treatment: Prepare some liquid fertilizer and pour it into the soil. Then increase the frequency of fertilizer, preferably every 10-15 days.

3, leaf rust

Cause: toon disease is mainly rotting roots, which is harmful to the roots of toon, resulting in root rot, which can not supply nutrients normally, leading to yellowing of leaves.

Treatment: the diseased leaves should be removed in time, fertilization management should be strengthened, and at the same time, 10% alkaline water, 10% anthracene oil, or 5% tolbutamide should be applied.