Common diseases and prevention methods of Kalanchoe

Kalanchoe leaf spot

Leaf spot disease mainly attacks the leaves of Kalanchoe. The affected parts of the leaves appear as brown spots. If not discovered in time, the spot area will expand into dark brown "patches" and will also infect adjacent Kalanchoe potted plants.

Treatment method: You can use carbendazim, thiophanate-methyl or thiophanate-methyl powder, prepare it into a water solution at a ratio of 1 : 200 , and pour it into the flowerpot. You can also use a spray bottle to spray the front and back of the leaves once every three to five days. Generally, it can be cured after three times. If the disease is serious, you can dig out the plant, rinse it gently with water, clean the soil at the roots, and then soak it in the prepared water solution for 2-3 hours. Then change the pot and soil and replant it, and water it thoroughly with the soaked water solution. After repotting, you should also frequently spray the front and back of the leaves with the prepared water solution. It will be cured after more than half a month. In spring and autumn, exposing the affected plants to more sunlight can also increase the plant's resistance, promote the absorption of medicine, and restore health faster.

Kalanchoe black rot

The main causes of black rot are compaction of the nutrient soil with poor air permeability, lack of ventilation at high temperatures, and excessive watering. It manifests itself in the roots of long-lived plants. The plants suddenly turn black for no reason while growing normally, and then quickly spread upward. As the blackened stems become soft and unable to support the upper branches, the branches hang upside down and the leaves become soft and wrinkled. The main characteristic of black rot is that the pathogen invades deep areas and the disease progresses quickly. If not discovered in time, the upper branches will turn black and die after a few days.

When encountering this situation, flower lovers should not be anxious. Just observe more and discover the disease in time. You can cut it off 1-2 cm away from the blackened part of the root, mix carbendazim, thiophanate-methyl or thiophanate-methyl powder with water, and soak the branches in the aqueous solution prepared at a ratio of 1 : 200 for 2-3 hours. Then use plain sand or vermiculite to re-cut the cuttings. The management is the same as above.

Kalanchoe mosaic virus (Green Island virus)

Mosaic virus is the most common virus of Kalanchoe, and it is extremely common in modern hybrid varieties. This virus only appears in harsh growing environments and is transmitted to the plant body through severe root infection, appearing as light green to yellow mosaic spots or patches on the leaves, with an uneven surface. In severe cases, it will inhibit the growth of the plant. Plants are most susceptible to this virus.

The treatment method is to cut off some branches, remove the diseased leaves, and then soak the branches in a carbendazim aqueous solution for about 5-6 hours for sterilization. On the other hand, the original roots must be discarded and the original pots and substrates must be sterilized; then the sterilized branches are re-cut into plain sand or vermiculite to promote root growth. It will take about ten days for the roots to take root. After about twenty days, when the roots grow to 1-2 cm long, they can be transplanted into nutrient soil (peat soil + perlite prepared in a 1 : 1 ratio, and a small amount of vermiculite can also be added); finally, the transplanted branches are placed in a place with moderate temperature and good ventilation to slow down the growth of the seedlings. After the leaves are in good shape, move them to a place with diffused light for maintenance. Wait until new leaves emerge before exposing them to full sunlight. (Avoid full sunlight in summer for longevity plants, as it will burn the leaves).

Powdery mildew of Kalanchoe

Powdery mildew is a fungal disease that primarily attacks leaves and stems. The affected parts appear white powdery, which is difficult to wipe off with hands or a brush. The leaves of the affected plants become weak and stop growing, and they look sick and miserable. Paris and lilac are most susceptible to this pathogen.

It is recommended to use potassium permanganate aqueous solution for treatment, but only in the early stages. If the powdery mildew is more serious, it is recommended to use sulfur powder. Mix sulfur powder with water into a paste, apply it to the affected leaves and stems with a soft-bristle brush, and sprinkle some sulfur powder on the surface of the substrate, and combine it with watering to promote root absorption. A month later, a miracle happened: the powdery lesions on the leaves and stems became lighter in color and the lesions shrank in size. After continued treatment, the leaves regained their luster and new branches began to sprout.