Identify the root cause of crop diseases through leaf symptoms

Read the leaves to diagnose the root of the disease

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Determine the root cause of the problem through orchid leaf characteristics: □Orchid leaves turn yellow but growth is normal: this is due to excessively strong light. □Orchid leaves turn yellow and new shoots are smaller: excessive light, lack of nitrogen fertilizer and necessary humidity. □Old leaves yellow and fall off: normal aging or caused by repotting. □Old leaves yellow and fall off rapidly: overwatering too frequently, improper repotting and planting. □New leaf tips scorched: excessive fertilization, unclean planting material. □Both new leaves and old plants have scorched black tips: excessive damp heat in the pot, with rotten roots among the root system. □New shoots stop growing after emerging from the soil: there are rotten roots or unclean matter beside the new shoots; uncover the growing medium around the new shoots and remove the unclean matter and growth will resume. □There are scorch spots on orchid leaves with no yellow around the edges: sunburn spots. □Leaf tips appear scalded and shrunken: the water temperature for watering is too high; the air temperature is too high when watering; exposure to sudden rain showers during high summer temperatures, etc. □New shoots have rotten centers: after water is poured into the shoot center, the moisture cannot evaporate and be absorbed, and the growing medium in the pot is unclean, producing leaf rot disease, etc. □There are spots on orchid leaves with water-soaked edges: excessive humidity, pot moisture combined with air humidity causing suffocation, accompanied by leaf rot pathogens. Poor ventilation and air circulation. □There are yellow-brown spots on the leaves: caused by the roots being overheated. □There are irregular yellow spots on orchid leaves, with the mesophyll tissue necrotic and sunken: caused by viral disease, also known as virus disease. □There are small yellow spots on the leaves: caused by scale insects. □Purple-black appears on orchid leaves while the underside remains green: caused by low-temperature frost. It can also occur with phosphorus deficiency. □Leaves dehydrated, pseudobulbs shriveled: caused by long-term excessive dryness and dehydration in the pot.