Treating common diseases in orchids

Despite good care, diseases can occur in orchids. Often the pathogens are brought in at the time of purchase. Basically, you should keep your fingers off plants in plastic film, because they are often infested with gray mold, even if you can’t see it yet.
Otherwise it is important to regularly check the orchids for signs of disease. The earlier you discover the first symptoms, the easier it is to do something about it. Once the disease has spread and attacked the entire plant, it becomes difficult and often the orchid can no longer be saved.

Leaf loss

It is normal for leaves to fall off. Every now and then a leaf that turns yellow and then falls off is nothing to worry about. In the case of the genus Dendrobium and Calanthe in particular, they lose all of their leaves before or after flowering. Phalaenopsis and Vanda also regularly separate from leaves, but individually, rarely two at a time. The fact that leaves fall off in the darker part of the year is mostly caused by light and cannot be changed unless you use plant lamps.

Fungal attack
Fungi are often the cause of leaf fall. They clog the conductor tracks. Transport within the plant can no longer take place. She dies. The first thing to do is to fall off the leaves. There are fungicides against fungal diseases.

Lack of light
Plants lack light, especially in winter. They get along with it for a while, sometimes even more than a year or two, but then they start to get sick and shed the leaves. Setting it brighter can save the plant if it is not too weakened.

Compacted substrate
If an orchid stands in the same substrate for too long, roots are often damaged and leaves are shed as a result. Mosses or algae in the substrate in particular ensure compaction. Only a small amount of oxygen reaches the roots. Therefore it should be repotted regularly, at least every two years.

Pests
Pests such as spider mites can also cause leaf fall. More information on this under: Pests on orchids – scale insects, mealybugs & Co

Brown spots on the flowers

These spots are caused by a fungus. Botrytis is promoted by spraying or excessively high humidity with little air movement. It is important to lower the humidity and stop spraying. In addition, fresh air must be regularly provided. If necessary, a paper handkerchief can be placed on the flowers in the evening. If the fungus is limited to the flowers, the orchid itself is not in danger, it is just a visual problem. If, on the other hand, the fungus spreads, action must be taken. Suitable fungicides are available in stores.

Falling flowers
If the flowers fall off before opening or shortly afterwards, there can be various causes. Precise research into the causes must be carried out here. Often there are location issues that need to be clarified.

Too warm a location
that is too warm or a place above the heater will not suit orchids. They are weak and ailing. First the flowers fall, later mostly the leaves too. Pest infestation is usually not long in coming. High temperatures are generally not good for the flowers. They only last a short time.

Drafts
When ventilating, you must always ensure that orchids are not in the draft. That doesn’t suit them at all.

Lack of light or direct sunlight
Too little light is often the cause of premature flower shedding. A light location helps here. Orchids cannot tolerate direct sunlight around noon, neither in summer nor in winter.

Change of location
Buds or flowers often fall off after a change of location. This also often happens after the purchase. The conditions at the retailer are very different from those at the new home.

Spots on the leaves

Spots on the leaves or the entire plant are often a sign of a fungal infection. Then the spots are brown or black and have sunk a little. They are spreading. However, it can also be burns from too much sun. Bacterial and viral infections are also possible and very dangerous.

Fungal infection Fungal
infections, also known as black spot disease, have brown or black spots, mainly on the leaves. They are often a little sunken, dry and spreading further and further. The infection is promoted by spraying the leaves or by giving too much water during the dry season. Possible causes are too much moisture, combined with a lack of light and cold or too high humidity with too little air movement.

• Cut off or cut out the infected leaves
• Thoroughly clean and disinfect cutting tools beforehand.
• Also disinfect afterwards so that the disease does not spread to other plants through the tools.
• Strictly isolate infested plants
• Improve culture conditions
• Stop spraying first
• Lower the humidity
• Provide more fresh air
• If it spreads strongly, spray broad-spectrum fungicide, but there are many fungi and not all agents help against precisely these
• As a home remedy – cinnamon. To do this, mix a teaspoon of ground cinnamon in a small cup with water. Stir vigorously until a connection forms. Apply the suspension to the leaves with a brush. It is best to brush the entire plant. Rinse off cinnamon after healing.
• It is also helpful to sprinkle the stains with charcoal powder.

sunburn

In the case of sunburn, there are large dry spots in brown-black, sometimes a little white in the middle. These spots do not spread and are a clear sign of too much sun exposure. There is nothing more you can do about it. The stains are permanent. It must be prevented that the plants are too sunny. Especially after the long winter, orchids have to slowly get used to more light and sun again. The plants are only at risk if the burns are too large.

Bacteria
Bacteria have an easy time of it, especially with soft-leaved phalaenopses. At first, small, brown, somewhat sunken, but sharply demarcated spots appear. It is typical that the tissue in and around the stains is damp or slimy, but this is not always the case. The spots get bigger. The leaf turns yellow and falls off.

• Isolate the plant immediately, disease is highly contagious
• Occur especially in the winter months
• An extra room is required. Everything has to be disinfected
• Plants (including neighboring plants) must be dipped several times separately in a suitable disinfectant (never spray !!!)
• Disinfect or throw away all vessels
• Cut away the damaged areas generously. Flame the tool after every cut.
• Always disinfect your hands
• If all of this is too costly for you, the plant prefers to dispose of it before more are infected

Viruses
Many small spots that can be seen in stripes, rings or arrows on the leaves indicate a virus infection. Identifying viruses is only possible with a specialist microscope. Still, there is nothing to help them. Fortunately, such infections are rare because attention is paid to them when they multiply. However, viruses can be transmitted through sucking insects.

Putrefaction

Putrefaction comes from too much water. This can affect the root area or water runs between the leaves, right in the center of the plant. The water standing there offers ideal conditions for bacteria that can multiply in large numbers in a short period of time. It is therefore important to always make sure that there is no stagnant water, neither in the container nor directly on the orchid.

• It is best to water in the morning so that excess water can evaporate during the day
• No too high humidity
• Lots of fresh air
• Weak plants are particularly susceptible, as are freshly repotted specimens
• If the heart rots, the orchid cannot be saved
• If individual parts are affected, these must be cut out
• Treat interfaces with carbon or sulfur powder
• Then keep the plant dry. She needs a lot of fresh air. Just pour carefully

Ziehharmonikawuchs

Accordion growth is clearly visible. You can also say wrinkle growth. The leaves have kinks and look like an accordion. The cause is longer pauses in growth, which are mostly due to irregular pouring behavior. Temperatures that are too high or temperature drops that are too low can also be triggers. Sometimes the crease cannot be prevented even under ideal conditions, but it is only a blemish, not a disease.

• No blanket remedy
• Look for the cause
• Change pouring behavior
• Lower temperatures

No flower formation

When an orchid grows well, develops, but refuses to flower, there can be several causes. Most of the time, however, the resting phase was not observed, which is simply part of the process for most species before flowering. During this time the plant is dormant, there is little watering and no fertilization. The temperatures have to be lowered. In order for the orchids to be properly cared for, you should inquire about the right cultivation measures when purchasing them, which will help to avoid mistakes in the care.

Frequently asked questionsDo sticky drops on orchids indicate a disease?
In Phalaenopsis and Cattleya, these drops are common and almost normal too. However, this increases with stress. You can often see the drops when the temperature difference between day and night is too great. It is often pests that are to blame.
Even if nothing is found, the drops should be rinsed off with a soft cloth and a little warm water. They attract lice and ants and you don’t want them in the house. In addition, the culture conditions should be improved.

What causes droopy leaves on the orchid?
If the orchid leaves are limp, soft or leathery and grooved, there is usually something wrong with the water supply to the plant. This can be caused by too much or too little water. Here the root has to be checked first. It has to be green and firm. If some roots are brown and / or mushy, too much water is to blame. Remove the mushy roots and repot the plant. Pour less. Light green or almost white roots are a sign of drought. Then it helps to put the pot in water so that the roots can soak themselves up. Increase humidity.