What is the problem of macula on the leaves of Cymbidium? How to prevent and cure it?

Clivia leaves yellow generally have several cases, if the bottom leaves grow new roots from the axils, so that the leaves yellow is a normal metabolism. A situation is that the axils do not produce new roots and the leaves turn yellow, it is mostly due to poor soil quality, poor air permeability, excessive fertilizer or poor control of watering humidity, which may make the leaves of Clivia yellow. Water irrigation is not transparent, root tip lack of water, it will make leaf tip yellow dry tip, appear this kind of situation, must irrigate water, in summer, every 7-10 days at the bottom of the flowerpot can sit a small basin of water, so as to ensure irrigation water, this is called immersion method.