How to prevent powdery mildew and gray mold on kalanchoe?
Kalanchoe is considered one of the easier succulents to care for, but it is also quite prone to powdery mildew and gray mold. So, in terms of care, paying attention to the following five points can effectively prevent powdery mildew and gray mold on kalanchoe.
Kalanchoe is considered one of the easier succulents to care for, but it is also quite prone to powdery mildew and gray mold. So, in terms of care, paying attention to the following five points can effectively prevent powdery mildew and gray mold on kalanchoe.
Kalanchoe
1. Try to keep the leaf surface dry and maintain good airflow between pots, and especially do not spray water in the evening, which would leave water on the leaves overnight. If there are water droplets on the leaves, blot them dry with a paper towel or blow them off with an air blower.
2. Focus on prevention, and regularly spray with a fungicide.
3. If the plant accidentally develops wounds or ulcerated areas, apply wood ash, sulfur powder, or thiophanate-methyl as soon as possible.
4. On days with high humidity and large temperature differences, pay attention to checking the condition of the plants, especially disease-prone varieties such as Paris and White Fox.
5. Once discovered, remove diseased leaves and branches as early as possible to reduce the amount of pathogens, and at the same time seize the opportunity to spray fungicide.
Disease control for kalanchoe: powdery mildew, gray mold, stem rot and root rot
Kalanchoe is one of the easier succulents to care for, but it can also develop some common diseases: powdery mildew, gray mold, stem rot and root rot. The author of the following text, Dingyun Zhishui, teaches you how to prevent and control the common diseases of kalanchoe. Some prevention measures and care methods are also applicable to succulents in general, so you may find them worth referring to."Powdery mildew mostly occurs from late autumn to early spring, and is likely to occur when the temperature difference between day and night is large and humidity is high. At night, when the temperature is
15°C and the humidity is as high as 90%, it is most suitable for the production, germination and infection of fungal spores. During the day, at a high temperature of 27°C and
40-70% low humidity, it is most suitable for the maturation and release of spores. ... It is inhibited above 30°C. The humidity range for onset is very wide, and the disease can occur at relative air humidity between 23% and 99%. Therefore, even in a dry greenhouse or under high-temperature and high-humidity conditions during the moldy rainy season, powdery mildew can still occur and spread rapidly."
"Gray mold is a low-temperature and high-humidity disease. The growth temperature of the pathogen is 2-30°C. When the temperature is 20-25°C and humidity remains above 90%, it is a period of high disease incidence. The pathogen tolerates low temperatures, produces large numbers of spores at 7-20°C, and at temperatures of 15-23°C. Under weak light, when relative humidity is above 90% or there is a water film on the surface of seedlings, the disease is likely to occur. It is most susceptible during the flowering period, and invades through wounds and senescent organs via airflow, irrigation and agricultural operations."
Understanding the mechanisms by which powdery mildew and gray mold occur, you should pay attention to the following points in care:
1) Try to keep the leaf surface dry and maintain good airflow between pots, and especially do not spray water in the evening, which would leave water on the leaves overnight. If there are water droplets on the leaves, blot them dry with a paper towel or blow them off with an air blower.
2) Focus on prevention, and regularly spray with a fungicide.
3) If the plant accidentally develops wounds or ulcerated areas, apply wood ash, sulfur powder, or thiophanate-methyl as soon as possible.
4) On days with high humidity and large temperature differences, pay attention to checking the condition of the plants, especially disease-prone varieties such as Paris and White Fox.
5) Once discovered, remove diseased leaves and branches as early as possible to reduce the amount of pathogens, and at the same time seize the opportunity to spray fungicide.
As a beginner, what you should pay special attention to is that when there is no lack of water, if you find that the kalanchoe plant is listless, and the leaves are shrunken, dry, wrinkled and dull, it generally indicates that there is a problem with the plant's root system. You should immediately repot the plant and wash the roots, and replace the growing medium. In severe cases, be decisive and cut off the head, taking the good part for cuttings. Do not simply assume that the plant lacks water or lacks fertilizer.
The most common causes of stem rot and root rot are an environment that is too warm and too humid, and wounds becoming infected with pathogens. Fungus gnats, moth larvae and snails boring holes in the stems, as well as root mealybugs, are all chief culprits. Therefore, to prevent stem rot and root rot, on the one hand you should develop good watering habits and try to avoid long-term waterlogging or excessive moisture, and on the other hand you should treat both pathogens and pests together.
Recommended medications for powdery mildew, gray mold, stem rot and root rot: tebuconazole, Syngenta Daconil 75% chlorothalonil 1000x solution, 50% thiram wettable powder 500-800x solution, 65% zineb wettable powder 600x solution.
If you cannot apply medication, you can also use baking soda at 1:1000 or a diluted vinegar solution to spray and wipe the plants.
By the way, pesticides, like flowers, also have hubs where counterfeit goods are gathered. It is recommended to do more research before buying medication, and it is best to look for well-known manufacturers or brands. Do not be penny wise and pound foolish. I know many beginners like to use carbendazim, thiophanate-methyl and the like recommended by pharmacies, especially the 1 yuan/packet kind. Even if you are lucky enough to buy the real thing, it can basically only be used to smear wounds, and is basically ineffective against fungal diseases such as powdery mildew, gray mold, stem rot and root rot. In addition, to prevent resistance, it is generally necessary to keep more than 2-3 kinds of fungicides and rotate them; alternating use is much more effective than using a single one.
In addition, cinder must be mentioned. Cinder is readily available and widely used in succulent cultivation. Many people only know that it has a drainage effect and can lower cultivation costs, but do not know that because cinder is rich in sulfur, it also has both fungicidal and insecticidal effects. Plants grown with cinder are more resistant than those without it, and are less likely to develop root rot and root mealybugs. (Reposted from Wudi Guodong Buding Xiong)
A brief discussion of pest and disease control measures for kalanchoe
Kalanchoe is one of the easier succulents to care for, but it can also develop some common diseases, such as powdery mildew, gray mold, stem rot, root rot, leaf spot disease, mosaic virus and so on. Below is a guide on how to prevent and control the common diseases of kalanchoe. Some prevention measures and care methods are also applicable to succulents in general, so everyone may find them worth referring to."Powdery mildew mostly occurs from late autumn to early spring, and is likely to occur when the temperature difference between day and night is large and humidity is high. At night, when the temperature is 15°C and the humidity is as high as 90%, it is most suitable for the production, germination and infection of fungal spores. During the day, at a high temperature of 27°C and 40-70% low humidity, it is most suitable for the maturation and release of spores. It is inhibited above 30°C. The humidity range for onset is very wide, and the disease can occur at relative air humidity between 23% and 99%. Therefore, even in a dry greenhouse or under high-temperature and high-humidity conditions during the moldy rainy season, powdery mildew can still occur and spread rapidly."
"Gray mold is a low-temperature and high-humidity disease. The growth temperature of the pathogen is 2-30°C. When the temperature is 20-25°C and humidity remains above 90%, it is a period of high disease incidence. The pathogen tolerates low temperatures, produces large numbers of spores at 7-20°C, and at temperatures of 15-23°C. Under weak light, when relative humidity is above 90% or there is a water film on the surface of seedlings, the disease is likely to occur. It is most susceptible during the flowering period, and invades through wounds and senescent organs via airflow, irrigation and agricultural operations."
Understanding the mechanisms by which powdery mildew and gray mold occur, you should pay attention to the following points in care:
1) Try to keep the leaf surface dry and maintain good airflow between pots, and especially do not spray water in the evening, which would leave water on the leaves overnight. If there are water droplets on the leaves, blot them dry with a paper towel or blow them off with an air blower.
2) Focus on prevention, and regularly spray with a fungicide.
3) If the plant accidentally develops wounds or ulcerated areas, apply wood ash, sulfur powder, or thiophanate-methyl as soon as possible.
4) On days with high humidity and large temperature differences, pay attention to checking the condition of the plants, especially disease-prone varieties such as Paris and White Fox.
5) Once discovered, remove diseased leaves and branches as early as possible to reduce the amount of pathogens, and at the same time seize the opportunity to spray fungicide.
As a beginner, what you should pay special attention to is that when there is no lack of water, if you find that the kalanchoe plant is listless, and the leaves are shrunken, dry, wrinkled and dull, it generally indicates that there is a problem with the plant's root system. You should immediately repot the plant and wash the roots, and replace the growing medium. In severe cases, be decisive and cut off the head, taking the good part for cuttings. Do not simply assume that the plant lacks water or lacks fertilizer.
The most common causes of stem rot and root rot are an environment that is too warm and too humid, and wounds becoming infected with pathogens. Fungus gnats, moth larvae and snails boring holes in the stems, as well as root mealybugs, are all chief culprits. Therefore, to prevent stem rot and root rot, on the one hand you should develop good watering habits and try to avoid long-term waterlogging or excessive moisture, and on the other hand you should treat both pathogens and pests together.
Recommended medications for powdery mildew, gray mold, stem rot and root rot: tebuconazole, Syngenta Daconil 75% chlorothalonil 1000x solution, 50% thiram wettable powder 500-800x solution, 65% zineb wettable powder 600x solution.
If you cannot apply medication, you can also use baking soda at 1:1000 or a diluted vinegar solution to spray and wipe the plants.
By the way, pesticides, like flowers, also have hubs where counterfeit goods are gathered. It is recommended to do more research before buying medication, and it is best to look for well-known manufacturers or brands. Do not be penny wise and pound foolish. I know many beginners like to use carbendazim, thiophanate-methyl and the like recommended by pharmacies, especially the 1 yuan/packet kind. Even if you are lucky enough to buy the real thing, it can basically only be used to smear wounds, and is basically ineffective against fungal diseases such as powdery mildew, gray mold, stem rot and root rot. In addition, to prevent resistance, it is generally necessary to keep more than 2-3 kinds of fungicides and rotate them; alternating use is much more effective than using a single one.
In addition, cinder must be mentioned. Cinder is readily available and widely used in succulent cultivation. Many people only know that it has a drainage effect and can lower cultivation costs, but do not know that because cinder is rich in sulfur, it also has both fungicidal and insecticidal effects. Plants grown with cinder are more resistant than those without it, and are less likely to develop root rot and root mealybugs.
Leaf spot disease mainly attacks the leaves of kalanchoe. If it is not discovered in time, the spots will expand into dark brown "patches." It can also infect adjacent potted kalanchoes, and White Fox and Friend are especially susceptible to this pathogen. Treatment method: you can use carbendazim, chlorothalonil or thiophanate-methyl powder, mix with water at 1:200 to make an aqueous solution, 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, and it can generally be cured after three times. If the disease is severe, you can dig out the plant, gently rinse it with water, wash off the soil ball around the roots, then soak it in the prepared aqueous solution for 2-3 hours, then repot it with fresh soil and replant it, and water it thoroughly with the used aqueous solution. After repotting, also frequently spray the front and back of the leaves with the prepared aqueous solution, and it can be cured after more than half a month. In spring and autumn, let the affected plant receive more sunlight, which can also increase the plant's resistance, promote absorption of the medicinal solution, and help it recover health faster.
In addition, mosaic virus is the most common virus in kalanchoe, and it appears extremely widely in modern hybrid varieties. This virus only appears when the growing environment is poor and is transmitted to the plant body by severe root infection, manifesting as light green to yellow mosaic spots or patches on the leaves, with an uneven surface, and in severe cases it inhibits plant growth. Feng Hua Xue Yue is most susceptible to this virus. The treatment method is, first, on the one hand, to cut some branches, then remove the diseased spotted leaves, and soak the branches in a carbendazim aqueous solution for about 5-6 hours for sterilization. On the other hand, you must discard the original root system and sterilize the original pot and substrate; then, replant the sterilized branches into plain sand or vermiculite to promote rooting temporarily, and they will take root in about ten days. After about twenty days, when the roots have grown to 1-2 cm long, they can be temporarily planted into nutrient soil (peat soil + perlite mixed at 1:1, and a small amount of vermiculite can also be added); finally, place the temporarily planted plants in a place with moderate temperature and good ventilation to recover. After the leaves perk up, move them to care under diffused light, and only after new leaves appear can they receive full sun (in summer, avoid full sun for kalanchoe, as it will scorch the leaves). This method was introduced to flower friends and also achieved the expected results.
Summary: The above are the pest and disease control measures for kalanchoe introduced for everyone. I hope everyone will summarize and exchange experience more.