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Orchids are a popular ornamental plant for many people because of their impressive flowers and tropical charm. It is one of the most demanding houseplants and can quickly suffer due to care mistakes. A typical problem is pest infestation by the insect family Coccoidea. The plant lice, with their characteristic shields, under which the young animals grow, are a nuisance for orchid owners because they reproduce quickly and rob the Orchidaceae of the important plant juices with their proboscis.

Where do scale insects come from?

Purchase already infested orchids

Scale insects get on the last nerve of orchid owners, as they appear within a short time and can damage the orchids severely. Nevertheless, the plant lice do not just appear like that, because scale insects become in most cases brought in. You should therefore examine the desired specimen particularly thoroughly when buying it, because even experienced breeders must always assume that it is infested with pests. To select a specimen that is not infested, do the following when checking:

  • check the underside of the leaves
  • feel free to use a magnifying glass as the animals are well camouflaged due to their colour
  • if one plant is affected, check the neighboring plants
  • in most cases these are also affected

Be sure to refrain from buying an infested orchid, even if the lice are dead. The number of young animals is extremely high and not all of them are immobilized, which quickly leads to a new infestation. Remember: you fight scale insects best if you don't bring them into your four walls.

care mistakes

Another cause of the lice is a weakened orchid. As soon as the care is not right, the plant is easily attacked, especially over the winter when the air is dry and too warm. Proper care is essential to prevent scale insects from growing on your orchids.

Control scale insects

Before using any home remedy

It is particularly important to irrigate affected plants before applying any remedy isolate, so that the lice cannot multiply further. It is best to place them in a separate room and check the other specimens for a scale insect infestation over the next few years. You can reduce the infestation somewhat if you thoroughly remove dead bracts and dispose of them in the household waste and repot the plant or provide its new substrate. This will get rid of a large amount of scale insects before using the home remedy, making the whole effort much easier.

Home remedies to get rid of scale insects

There are a variety of home remedies to combat coccoidea. In most cases, these are cheap and can be obtained within a short time. It doesn't matter where or from which manufacturer you get them, as fast action is required in the event of a scale insect infestation. The lice can multiply extremely within a short time and can even infest plants of other genera or families. For this reason, you should choose one of these home remedies to combat the annoying pests. However, keep in mind: if the leaf drop due to the pests is in full swing, the plant can usually no longer be saved.

tip: avoid using a knife to collect the scale insects as this would lead to a larger infestation. The agile young animals hide under the shields of the mother animals for a long time and find a place on the plant themselves as soon as the shield, i.e. the mother animal, is separated from the plant.

rubbing alcohol

Isoproanol, also known as rubbing alcohol, is an effective solution against lice because the high-proof alcohol penetrates the shield and kills the animals. However, you have to be very careful with this method, since sensitive orchids with soft or thin leaves, for example Kahn orchids (bot. Cymbidium) in particular, could react to this household remedy with a drop in leaves. You should use the product every 14 days until all scale insects have been removed. Proceed as follows:

  • soak a clean cotton cloth in isoproanol
  • use it to treat the tops and bottoms of the leaves
  • be careful not to drip alcohol onto the substrate or exposed roots
  • as soon as scale insects are no longer visible, stop treatment

tea tree oil

Tea tree oil is used in a similar way to control scale insects on orchids. However, tea tree oil is gentler than isoproanol, but is more expensive in comparison. The oil prevents the lice from breathing, which kills them quickly and effectively. All you need is cotton swabs and of course a bottle of tea tree oil:

  • put a few drops of tea tree oil on a cotton swab
  • apply this directly to the lice's shield
  • take your time with this, as this treatment may take a while
  • Also, be careful not to wet the leaves of the orchids with the tea tree oil
  • this reduces the risk of a possible leaf shedding by the oil
  • apply here every two weeks until the orchids are freed from the pests

Olive oil spray and dishwashing liquid

Sprays are particularly effective when treating your orchids. Olive oil and washing-up liquid have proven their worth here. Apply this as follows:

  • mix a liter of water with two tablespoons of olive oil and a few drops of dish soap in a spray bottle
  • it doesn't matter what kind of olive oil it is
  • spray the spray directly onto the affected leaves
  • treat the leaf axils with a brush
  • repeat this process once a week for a period of three weeks

Sprays made from soft soap and denatured alcohol

You can also use soft soap and denatured alcohol to combat scale insects on orchids:

  • mix 15 grams of soft soap and ten milliliters of denatured alcohol in one liter of water
  • do not apply the solution via a spray bottle, but with a brush
  • the spray is quite aggressive, so the treatment must be done with a brush
  • use the solution weekly until all lice are removed

fern broth

The use of fern broth as a spray has proven itself for orchids. With this you mainly fight mealybugs (Pseudococcidae), also called mealybugs. These belong to the scale insect family and have greasy hairs. Prepare the fern broth as follows:

1. Soak either 100 grams of fresh or 10 grams of dried fern in water for 24 hours. Then boil the broth for 30 minutes.

2. Then allow to cool, strain and fill into a spray bottle.

3. Now the broth is sprayed directly onto the affected areas twice a week. You can continue to use the fern broth even after the infestation, as it has a preventive effect. However, in the case of a severe infestation, it is not sufficient on its own and should be used together with other means.


Diatomaceous earth is also very effective and does not harm the plant. Diatomaceous earth is fossil diatoms that are ground up and spread as a powder directly onto the leaves using a nylon stocking or similar material. Leave the powder on for 90 to 120 minutes and then rinse off with water. Repeat this process weekly until all lice are removed. Where do you get diatomaceous earth from? Hardware stores, mail order and specialist dealers for viticulture and poultry farming. Diatomaceous earth is quite cheap and very economical. Three kilograms cost about 15 to 20 euros.

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