The leaves of the chrysanthemum have yellow spots
Main content guide: Related content of Chrysanthemum Clinic, chrysanthemum leaves with yellow spots, details are as follows:
When yellow spots appear on the leaves of chrysanthemum, besides the normal growth physiological laws, that is, the general leaves survive on the plant for about 3 years and the old leaves turn yellow, age, and naturally fall off, which has no side effects on the plant. This is the normal process of metabolism and growth of chrysanthemum. However, yellow spots appearing on new leaves or unripe leaves are abnormal phenomena.
The main symptoms of leaf spot disease are yellow or brown small spots on the leaf surface, which gradually deepen in color, and the area of the spot ulceration gradually expands, which can cause the leaves or the whole plant to rot.
The main causes of leaf spot disease are: first, the application of unfermented fertilizers, which allows pathogens to multiply in the potting soil; second, the potting soil has not been changed for a long time, and there are pathogenic bacteria in the old soil; third, the new soil is not fully fermented and ferments again in the pot; fourth, the imbalance of nitrogen, phosphorus, and potassium fertilizers, especially the lack of potassium fertilizer or direct contact of fertilizers with the roots during application. Different methods should be taken to prevent and cure according to specific reasons. The applied fertilizer must be fully fermented, the concentration of fertilization should be low, nitrogen, phosphorus, and potassium should be balanced, and the nutrient soil should be fully fermented and changed twice a year in spring and autumn. Do not use raw soil. This can prevent the occurrence of leaf spots.
The main symptoms of yellow leaf disease are:
A part of a leaf turns yellow, the yellow part has no regular pattern, the tip of the leaf turns yellow first and then spreads to the pseudobulb, the pseudobulb turns yellow first and then gradually spreads to the leaf tip, and the entire leaf turns yellow from the bottom to the tip at the same time. The first situation is caused by the leaf surface being sunburned, damage from cold wind, local bites by pests such as snails and slugs, or the expansion of wounds after injury. The main reason for the yellowing of the leaf tip is that the root rot causes the interruption of nutrition (G-Y) in the leaves, starting to turn yellow from the tip to the pseudobulb. The use of raw soil or poor soil quality can also cause this phenomenon. The cause of the third situation may be due to pest bites on the pseudobulb, causing it to gradually spread to the tip, or water accumulation at the pseudobulb during summer, leading to bacterial growth and local yellowing of the leaves. The simultaneous yellowing of the entire leaf is more common, and the causes are more complex, mainly due to improper management. For example, poor ventilation in summer, excessive watering, excessive fertilization, and root problems can all cause the entire leaf to turn yellow.
Preventive measures include preventing root rot, ensuring that the leaves get sufficient nutrition, preventing wounds, and controlling the amount of fertilizer applied. It is important to avoid over-fertilization. Adult flowers should not be watered near the pseudobulb in summer, and ventilation and cooling should be strengthened, with regular spraying of fungicides such as carbendazim, thiophanate-methyl, and agricultural streptomycin for prevention and treatment, which can reduce and prevent the occurrence of leaf spot and yellow leaf diseases.
This article shares how to deal with yellow spots on chrysanthemum leaves as a reference suggestion for everyone.