Healthy plants can usually fight off the infection on their own Orchid Diseases or pests, but for stricken orchids they often mean death without proper treatment.
Black spots on the leaves are usually a sign of a sick orchid. But often your houseplant just has a sunburn. Photo: iStock/RHJ
Black spots, small holes or fine white webs? If you discover signs of a pest infestation or a disease on your plant, you need to act quickly – because this is the only way to prevent your orchid from infecting other plants within a very short time.
– Step 1: Immediately send the infested orchid into quarantine! – Step 2: Remove leaves and other plant parts infested by bacteria or viruses with a sharp and disinfected knife. – Step 3: Identify the Orchid disease and treat them. – Step 4: Examine your other plants for pests and diseases. – Step 5: Find the causes in your plant care and fix them!
Orchids are popular, but stubborn houseplants that require a lot of care
Orchids: An overview of pests, fungi, viruses& Co.
A sick orchid Can have many different causes – often a plant just seems floppy because it lacks water or the location is not ideally chosen. However, if you do not change anything then, you risk a permanent weakening of the orchid, which thus becomes an easy victim for pests, fungi, viruses and bacteria.
Orchids infested with pests are not exactly rare – often the small pests are already brought into the home with the purchase. Therefore, always examine a new plant closely for diseases as well as pests. If possible, do not place them near other plants after moving in.
Scale insects: The group of scale insects is one of the most common pests on orchids. Especially mealybugs and mealybugs attack the houseplants. While healthy plants fight off the pests with their own forces, the little animals, which range in size from 0.5 to 5 mm, can cause death in weak plants if left untreated. With their proboscis, the aphids suck the plant sap from the leaf veins of the orchids – they particularly prefer thick-leaved genera such as the Phalaenopsis or Cattleyas. The damage is usually noticeable in the form of wilted, deformed or sticky leaves, leaf loss and leaf discoloration. In case of severe infestation, the plant looks like it is wrapped in white absorbent cotton. Caution: Not only does the primary damage weaken houseplants, the puncture sites serve as excellent entry points for fungi. There is also a risk that the insects will transmit viruses to the plant.
If you want to use pesticides to control mealybugs on orchids, they should definitely be systemic! Photo: iStock/legna69
For successful control of scale insects, the earlier the better! Accordingly, it is important that they regularly examine your orchid for an infestation. Pay particular attention to the undersides of the leaves. The spaces between the bracts – this is where insects like to hide. If you notice a pest infestation, immediately isolate your houseplant from other plants! You can then carefully remove the bracts to deprive the aphids of their safe hiding place. A particularly effective and at the same time gentle method of removal is spraying with a mixture of about one liter of water, two tablespoons of olive oil and a splash of dishwashing liquid.
Spider mites: Spider mites attack orchids especially in summer or during the heating season, as they require high temperatures and low humidity to reproduce. The pests, which are about 0.25 to 0.8 mm in size, sit on the underside of the leaves, feed on the plant juices and spin fine white webs, which often only indicate the problem when the infestation is already extensive. Spider mites occur worldwide. Can attack several hundred plant species. In this country, the common spider mite is the most common.
Before treatment, you should immediately quarantine infected plants so that the infestation does not spread. Shower the little animals. Thoroughly rinse your small nets with water first. The use of neem oil has proven to be particularly effective. Simply mix a liter of water with 1-2 tablespoons of neem oil. Spray your orchid once a week for about three weeks. Attention: Do not expose your houseplant to direct sunlight after spraying, as the neem oil would burn the leaves of the plant. In addition to control, proper care of your orchid is key to prevention – be sure to keep humidity higher during warm periods!
Aphids: The small pests attack orchids rather rarely, but in case of an infestation, quick action is required. The aphid not only sucks the sap from the orchid with its proboscis, it is also a carrier of many viruses and fungal diseases. Depending on the species, the small animals are yellow, green or black and usually settle in groups on the undersides of leaves or other parts of the plant. A special warning sign is sticky residue on or near the plant – the so-called honeydew is excreted by the aphid and attracts ants.
Once aphids have infested the plants, you need to act quickly
But what to do when orchids are sticky? To remove the aphids, you should shower the plant thoroughly. If that's not enough, a soft soap solution can help: mix one tablespoon of liquid soft soap with one liter of water and spray the plant with the mixture every two days for about three weeks. Chemical agents can also be used against aphids – but if you want to avoid this, here are 7 more home remedies against aphids!
Other pests that can attack orchids are, for example, the larvae of fungus gnats, thrips or snails. To avoid an untreatable pest infestation, you should regularly inspect your houseplants for bugs. You should take a particularly close look at the undersides of the leaves!
The most common fungal infections in orchids are the so-called black spot disease on the one hand and gray mold rot on the other hand. As is usually the case with a fungal infestation, the outbreak can be traced to certain factors in the care of the plant. Especially high humidity, too frequent or simply wrong watering as well as poor air circulation contribute to the development of fungi. If the fungal infestation is detected early, you can control it without using chemical fungicides. It is important to isolate immediately and remove affected leaves and other plant parts such as rotten roots with a sharp, clean knife.
As a rule, orchids only rarely need to be cut back. If possible, cut the stems of your orchid only when they are.
Afterwards, keep the plant as dry as possible, watering only in the morning and ensuring adequate air circulation. The best remedy against a fungal infection is a strong and healthy plant.
Unfortunately, orchids are also repeatedly affected by viral diseases. The pathogens of so-called mosaic viruses, which owe their name to the mosaic-shaped discolorations on young leaves of houseplants, are particularly common. Viruses are mainly transmitted to orchids by pests or unclean cutting tools. Can not be treated with home remedies or chemical pesticides. If you notice a viral disease on your plant, it is important to isolate it immediately, remove affected parts of the plant with clean pruning tools and provide the plant with the best possible conditions to fight it. It is then especially important to control possible pests as the cause of the Orchid disease.
Orchids are fortunately rarely affected by harmful bacterial pathogens. Only two genera – Erwinia. Pseudonomas – occur in orchids. The cause is usually an over-supply of water or excessive humidity. As with viruses, no chemical means can be used to control bacteria. So remove affected plant parts. Keep the orchid as dry as possible!
Proper orchid care: identify causes and prevent disease
Pest infestation and orchid diseases can affect any plant – it is only important that you recognize the problem early, eliminate the causes and thus prevent a spread or a new infestation.
Practical tip: vigorous orchids are also more resistant to orchid diseases. Optimal fertilization makes your orchids strong against pests and parasites. The video shows everything you need to know about fertilizing:
Early signs of diseased orchids:
In order to be able to help an affected orchid, the first requirement is of course to diagnose it as early as possible. Regular observation of your plant will help you to do this. As soon as you notice any of the following signs, urgent action is required:
– The orchid loses a noticeable number of leaves – The leaves of your orchid grow crumpled (accordion growth) – The orchid shows sticky drops on its leaves – The plant lets its flowers droop – The petals show spots – No flowers are formed for a long period of time – The substrate becomes moldy – Parts of the plant are rotting
Identify causes of orchid disease:
Healthy orchids with good care can defend themselves well against most pests, viruses, bacteria and fungi. However, if cared for incorrectly, the plants' defenses are usually insufficient. Accordingly, you should always check your plant care in the event of an infestation. To do this, shimmy along the following questions:
– Is my plant in the ideal location? Is my watering rhythm adapted to the location. The genus adapted? – How high is the humidity? – Are my plants attacked by pests? – Is my orchid in the right substrate?? – Is the orchid pot ideally chosen?