Hardly anything is more depressing for a hobby gardener than to see your own plants suffering from a pest infestation. Treatment becomes all the more difficult when the insects are scale insects. Using chemical agents is not always the best way. The use of insecticides is particularly problematic for crops or in your own four walls.

Hardy pests

More than 4000 different species of scale insects are known worldwide, some of which are particularly widespread in our latitudes. These include, for example:

  • mealybugs
  • Lid scale insects
  • scale insects
  • Mealybug
  • Spindle Scales

All female scale insects form special protective covers, which, depending on the species, consist of resin, wax or substances similar to spider silk. Under this extremely stable shell, not only do the eggs lay and the young animals develop, but the pests also feast undisturbed on the nutritious cell sap of the host plant.

Popular host plants

Even if scale insects are considered relatively undemanding when it comes to choosing their plants, they are particularly common on exotic houseplants and palm trees, such as:

  • Oleander
  • Flamingoblumen
  • ivy
  • rubber trees
  • Ficus
  • ornamental asparagus
  • Anthurium
  • window leaf
  • Phalaenopsis


In the early stages of infestation, the plant is covered with a sticky substance made from scale insect excrement. If the pest is not recognized and combated immediately, further damage to the plant occurs. The scale insects secrete a toxic secretion while eating, which gets into the organism of the plant and destroys it from the inside out. Symptoms of an infestation can include the following:

  • A white coating forms on the leaves.
  • Shoots appear encrusted.
  • Deformations occur in flowers and leaves.
  • Discolouration and premature shedding of the plant leaves follow.

Unwelcome beneficiaries

Scale insects rarely come alone. Their sticky excretions, the so-called honeydew, not only provide the blackspot fungus with a source of food, but also attract ants. They literally defend “their” lice against their natural predators. You should therefore not only fight the pests themselves, but also ants and fungi in equal measure.

Note: Before using natural predators, the ants must first be removed. Distract the animals from the scale insects with sugar water.

The first steps

Female scale insects produce up to 2000 eggs per year. The lice population therefore grows rapidly and neighboring plants are also quickly populated by the damaged insects. In order to curb the spread, infested plants in pots must be immediately isolated from other plants. You can also support the measures against the infestation with the following points:

  • Provide sufficient fresh air.
  • Direct and long exposure to sunlight
  • Spray the leaves and shoots with water daily.
  • Generate fluctuating temperatures.

Effective measures against the harmful insects

Treatment against a scale insect infestation is extremely difficult. The animals are not only extremely robust due to their “protective shell”, but also develop resistance to the agents used within a very short time. Whether these are industrially manufactured products or home remedies is irrelevant. Nevertheless, chemical insecticides should be the last resort, because they not only work against the pest, but also against beneficial insects and plants.

However, with a little patience and the right tips, you can also successfully combat your plants with biological means.

Useful helpers

Natural enemies of scale insects literally like to “eat” them. The following insects will help you to at least visibly reduce the aphid population on your plants:

  • ladybug
  • parasitic wasps
  • hoverflies
  • lacewings
  • predatory beetles such as Rhyzobius

None of these insect species listed can perform miracles and completely destroy a scale insect population. However, do not underestimate the natural predators, because in combination with additional treatment measures, scale insects will soon be a thing of the past. You don’t have to collect parasitic wasps and co. in the garden or forest yourself, because some of these insects are also easily available from specialist retailers.

With the right home remedies to success


For an effective brew you need:

  • 500 milliliters of warm water
  • 100 grams of alum powder

Both components are mixed well together. Just before you wet the scale insects with the tincture, the broth has to be diluted again with about 4 liters of water. Otherwise, in concentrated form, it causes considerable damage to the plant.

Nasturtium infusion

This brew is also very effective against scale insects:

  • 200 grams of nasturtium
  • 1 liter of water

Bring the ingredients to a boil and then steep for half an hour. This extract is also diluted again with 2 liters of water shortly before use and sprayed over a large area on the affected parts of the plant.

Farnkraute extract

Even larger plants – such as fruit trees – are by no means spared from scale insects. With such dimensions, dabbing the individual animals is difficult or almost impossible. A decoction is made with the fern extract, which can easily be sprayed over the entire tree.

  • 10 grams of dried fern or else
  • 100 grams of fresh ferns
  • 1 liter of water

The solution is diluted with 10 liters of water immediately before use. Repeat this procedure weekly and extensively.

Solution of alcohol and soft soap

This aggressive mixture is not compatible with all plants. First test on a small leaf or side shoot to see whether your ornamental plant is also sensitive to it. If this is not the case, you can take action against the scale insect infestation. For the remedy you need the following ingredients:

  • 30 ml denatured alcohol
  • 30g soft soap
  • 2 liters of warm water

Leave the mixture for about half an hour and then apply directly to the lice with a Q-tip or a brush. Treatment is daily.


This treatment method is not entirely harmless, but very effective. Mix the following components together in a sealable container:

  • 150-200 grams of tobacco
  • 1 liter of hot water

The mixture is not immediately ready for use, but is left for about 1 hour. Then carefully dab the scale insects and their preferred shoots with a small brush. Repeat this procedure every two to three days. You can also spray non-sensitive plants directly with the decoction. However, avoid skin and eye contact as this decoction has an aggressive effect on the mucous membranes. Pets and small children should never come into contact with the product.

soapy water

Make a sud from real curd soap and warm water. Wipe the affected parts of the plant with a cloth. This method is long-term and must be repeated regularly.

tea tree oil

No mixture is necessary here, apply the oil directly to the pests with a cotton swab. If possible, keep the shoots and leaves of the affected plant away from the oil.

Accompanying treatment measures

The sole use of the methods listed above is hardly effective, but in combination with other control measures they help you effectively in the fight against scale insects.

Garlic cloves

Peel a few cloves of garlic and plant them in the ground around the affected plant. The pungent odor is said to discourage some species of lice from laying eggs directly into the substrate. This method tends to have a long-term effect. But even if you no longer discover scale insects on the houseplant itself, leave the garlic cloves in the ground for a few weeks.

olive and paraffin oil

The pests cannot develop any resistance to oily substances. Because these do not act as a contact poison, but rather clog the respiratory openings of the scale insects. For a period of two weeks, the visible animals are brushed thinly with the paraffin or olive oil twice a day. Success is not immediate, which is why you should only take this step at the same time as other treatment measures.

Note: Do not bring oily substances into contact with the leaves and shoots of the plant.

Shaving and scraping off the scale insects

With a small, sharp knife, the pests are removed along with their thick shell. Proceed with caution, as there may already be fully developed young animals under the protective cover. If these spread further through the plant, it will make treatment more difficult. Also, you should never injure yourself or the shoots with the knife.

denatured alcohol

Not entirely harmless, but still effective: spray plants standing outside with denatured alcohol. Do not inhale the toxic fumes yourself and repeat the process no more than two to three times. After that, the scale insects could develop a resistance to the alcohol.


Strange as it sounds, improper plant care can be a significant contributor to scale insect infestation. Therefore, make sure that all the needs of ornamental and useful plants are met. Above all, it is important to avoid the following points:

  • too dry air
  • over-fertilization
  • nutrient deficiency
  • too little or too much light
  • lack of water
  • waterlogging

Especially in the winter quarters, it is important that the sometimes exotic plants are not exposed to dry heating air for too long or even permanently. Give the plants fresh air regularly and place containers filled with water in the immediate vicinity. This not only promotes the well-being of the plants, but also contributes to your own health.

error in combat

The successful fight against scale insects depends on the right combination of home remedies as well as perseverance and regularity. The pests will not go away overnight, so be patient. The following problems can often occur:

plant dies

It is almost inevitable that the affected parts of the plant die off. Because in addition to the scale insect infestation, the plant comes into contact with sometimes aggressive agents when fighting it. Remove the affected regions and dispose of them with normal household waste. Often immediately after successfully destroying the scale insects, the plant will start to produce new shoots.

Scale insects continue to multiply

This can have several causes and is often not uncommon even during successful treatment. In addition, not all scale insects can always be seen at a glance.

  • Combine different countermeasures.
  • Repeat this regularly.
Tip: Even if the scale insects are no longer visible on the infested plant, you should still continue with the d. Repeat all previously applied measures for about two weeks.

Repot the plant immediately after the last treatment. Some scale insect species are known to lay their eggs in the substrate. Of course, it can also happen that fighting with a home remedy alone is not successful. Work with two or three different methods so that the scale insects cannot develop a resistance to a remedy in the first place.

An infestation with the robust pests is by no means a reason to throw the affected plants in the garbage in frustration or resort to chemical insecticides. With the right tips and tricks, you can also get rid of scale insects in a biological way.

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