How to fight scale insects

How to fight scale insects

the essentials in brief

  • Scale insects are difficult to spot at the beginning; sticky coating indicates an infestation
  • Scale insects can be fought well with home remedies such as oil, dish soap, garlic or milk
  • Beneficial insects such as parasitic wasps, (14.59 € at Amazon *) ladybirds or hover flies are good helpers in the fight against scale insects

How to recognize a scale insect infestation

It is usually not difficult to identify a scale insect infestation on your plant. Unfortunately, the pests are not clearly visible right from the start, so that damage has often already occurred before the plant shows signs of infestation. Look out for indications that the leaves are sticky on the upper side of the leaves or that a whitish coating is formed. This sticky substance is the “honey” of the scale insects. This honey also attracts ants, for example, which is why their appearance is another sign of the presence of scale insects. Further indications can be encrusted shoots, deformed flowers and leaves as well as discoloration or loss of leaves.

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  • Fight scale insects on olive trees effectively and sustainably
  • How to control scale insects on orchids using natural means
  • Effectively control scale insects on oleander

Many ways and means of combating it are possible

In order to combat scale insects effectively and permanently, you should act quickly after recognizing the infestation in order not only to save the plant itself, but also to prevent an infestation of other plants in the vicinity. The following immediate measures can help:

  • Isolate the infected plant (as far as possible) and keep it in a light and cool quarantine. Cold can already help get rid of scale insects;
  • Remove badly damaged or dead shoots and flowers;
  • Rinse sturdier plants with water.

In addition to the immediate measures to prevent spreading, a suitable means of repelling the pests must be selected. There are a variety of products and approaches that come into question. The selection always depends on how strong the infestation is, what kind of plant it is and whether it is in the interior or in the garden. In addition, a home remedy can also be used in many cases, so that chemicals can often be dispensed with. There are also options for manual, biological and chemical control and for the use of beneficial insects.

fight against schildlaeuse

Toothbrush and water: mechanical removal

In most cases, the mechanical removal of scale insects does not work as a stand-alone approach to control, but can be used as an immediate first measure, especially in the case of severe infestation. Take a water hose and a toothbrush for plants in the garden or a wet washcloth for plants indoors and start manually to wash off the leaves completely and to wash away the honeydew and any visible scale insects. The toothbrush or rag should then be scrubbed over the entire plant at a right angle to the branch or twig.

Make sure, however, that you only apply as much pressure as your plant can bear without further damage - it is better to forego mechanical removal if you are dealing with sensitive plants. Citrus plants and palms, for example, benefit greatly from this measure, as treatment with a toothbrush does not affect them. It is best to repeat the process again after a few days to be sure that you have removed all the animals.

Insider tip: use home remedies

Mealybugs and scale insects can also be controlled systematically with many home remedies, which opens up a variety of possible approaches. It is best to test the selected home remedy on an inconspicuous leaf after a previous mechanical removal before you treat the entire plant with it - this will prevent the plant from being further damaged by an intolerance. The following can be considered as home remedies for combating scale insects:

  • Oil;
  • Alcohol and alcohol;
  • Soap and detergent;
  • other plant products;
  • Coffee, tea and milk; such as
  • Tobacco or nicotine.

Various oils

When it comes to organic home remedies, various oils have proven to be useful pests against scale insects. The oil structure sticks the scale insects' airways, which is why they suffocate within a short time. Since oil is not a contact poison, you can benefit from a fairly natural fight. Use rapeseed oil, tea tree oil, neem oil or olive oil and coat the visible animals with it every day for two weeks until you can no longer see any scale insects. Since this process is tedious, it is recommended in combination with other home remedies. The process can also be speeded up if you mix the oil with water and spray it all over the plant.

Alcohol and alcohol

You should proceed with caution when using alcohol, as it could damage many sensitive plants. Spirit is particularly recommended if your plant has a thick skin - such as cacti or palm trees. Mix high-proof alcohol or denatured spirit with a little water and press the mixture onto each individual scale insect as long as the infestation is still low. The mixture penetrates the pests' armor and kills them. Subsequent repotting is, however, strongly recommended.

Soap and detergent

A mixture of detergent, water and vinegar can also help. Spray the affected plant completely with this mixture and leave it for a few hours before you shower the plant well. Various effective combinations are possible here: for example, pure vinegar or soapy water or a mixture of water, washing-up liquid and alcohol also work if the plant is more robust.

Make sure that the soap you use is free from fragrances and other artificial additives so that the plant can be treated as gently as possible. It is therefore a good practice to use pure curd soap and dissolve it in water to make the detergent yourself. Soft soap (17.27 € at Amazon *) is even better suited for the production of soapy water, as it dissolves more quickly in water due to its consistency.

fight against schildlaeuse

Use other plants: garlic or nettle

In addition to the other biological approaches and home remedies, there is also the possibility of using the power of plants for your own purposes. For example, a minor infestation can be contained if you stick garlic cloves in the soil of a potted plant, which drives away the garlic-hating pests. Alternatively, you can boil a stock with chopped up garlic and apply it with a spray bottle.

In the garden in particular, it is a good idea to make liquid manure from nettles. It is not advisable to do this indoors as the liquid manure develops a strong odor. Soak nettles covered in a large container of water for three days and stir the mixture daily. Then filter the resulting manure and apply it repeatedly to the affected plants.

Coffee, tea and milk

All coffee and tea drinkers can also use their habit of making their own home remedy for pest control. Take the cold leftover coffee grounds or the cold, brewed tea leaves and mix them with water and then spray the mixture generously on the plant. A combination of tea and coffee has also proven effective - and creates a pleasant scent in the home. You can also put the coffee grounds directly on the soil in the pot, where it acts as a pest control and fertilizer. Alternatively, a mixture of milk and water can be used. For this, however, the milk should be briefly boiled beforehand and then poured cold over the plant.

Tobacco or nicotine

The last home remedy is tobacco or nicotine. Pour hot water over tobacco or cigarette ash and let the mixture stand for about an hour before sifting it and brushing or spraying it on the infested plant. Tobacco or cigarette ash on the potting soil can also increase the desired effect. But here, too, caution is advised: this procedure is not for sensitive plants!

Special combat from the trade

In addition to combating scale insects with home remedies, which in some cases can be done without chemicals, there are also special pest and pesticides in specialist shops. The advantage of these means is that the effectiveness is particularly high and the control is therefore permanent and effective. Make sure not to use any biological contact poisons such as pyrethrum, as these cannot penetrate the shell of the scale insect and are not very effective, but could negatively affect other insect species in the garden. Beneficial insects are also commercially available and, depending on the type of scale insect, can be exposed to the plant as a natural predator.

These funds are suitable

Suitable agents for chemical control are, above all, ready-to-use oil-based sprays such as Neudorff Promanal. This agent suffocates the pests, gives the leaves a beautiful sheen and at the same time does not affect other endangered insects (such as bees). Sprays based on Lizetan can also be used well for control purposes. Lizetan is particularly gentle so that it can also be used on sensitive plants such as orchids. The spray not only reaches the visible scale insects, but also the hidden pests, which is why a single treatment is sufficient in many cases. In addition, sticks containing this active ingredient can be used for indoor plants.

For experts: use beneficial insects

Scale insects predators

Finally, there is also the possibility of targeting scale insects with the targeted use of beneficial insects. However, this approach requires some expert knowledge, since not every scale insect is fought with the same beneficial insects. The advantage, however, is that this is a particularly natural type of pest control. It is best to contact a professional so that they can help you determine the type of scale insect and select the beneficial insect. In most cases, one of the following insect species is used:

  • Parasitic wasps;
  • Ladybug;
  • Hoverflies; or
  • Predatory beetle.

Good plant care can help prevent scale insects

If your plant is affected by scale insects, it is in most cases a symptom: scale insects mainly attack plants that are not in good condition. This is why scale insect infestation is more common in winter or spring when the plants have to get along with little light. If you have to fight scale insects, it is advisable to prevent a renewed infestation as well and to pay particular attention to the care of the plant after the elimination. Above all, this includes these measures:

  • Make sure your plant gets enough light;
  • Pay attention to the indoor climate with indoor plants and avoid that they are too warm;
  • Avoid nutrient deficiencies and use only small amounts when fertilizing with nitrogenous products;
  • The earth must be sufficiently loosened;
  • Pour with enough water and make sure that waterlogging does not build up.

In the case of fruit trees in particular, it can also be useful to treat the trunk with suitable cattle care and to encourage beneficial insects to multiply in the garden.


There are many types of scale insects

Not all scale insects are created equal: there are actually over 4,000 different species of this pest that infects and destroys plants. If you have discovered an infestation, it is worth taking a closer look at the culprit as a first step. The color and shape of the shell provide information about what type it is. It is often the case in our latitudes that one of the following scale insect species is responsible for damaging your plant:

  • Lid scale insects : These black, black-brown to brown scale insects are characterized by a flat lid that can be easily removed with a needle. It belongs to the largest group of scale insects and is very widespread.
  • Cup scale insects : Cup scale insects are also widespread and are black, black-brown or brown in color, and sometimes reddish. In contrast to the lid scale louse, however, the lid is arched and fused with the skin of the back, so that it cannot be lifted.
  • Comma scale : These gray to white scale insects have an elongated, also slightly curved cover and are mainly found on fruit trees. The name comes from the shape of the pest.
  • Cochineal scale insects : Cochineal scale insects have a purple-red body that is coated with a white to gray wax. Because their body contains a high concentration of carminic acid, the pests appear bright red as soon as they are crushed.
  • Mealybugs : This is a subspecies of scale insects that can be easily identified by the fact that it produces and leaves a substance on the leaves that looks like little white cotton balls.
  • Aphids : In contrast to scale insects, these pests are significantly smaller and differ in appearance from scale insects. Along with snails, they are one of the most common pests in the garden.
Scale insects varieties

Omnivorous scale insect: various plants can be affected

Mealybugs and scale insects are not gourmets, but real omnivores. They can be found on almost every type of tree and crop, regardless of whether it is in the garden or indoors. In fact, there are some plant species that are particularly popular with scale insects. These include the following in particular:

  • Citrus plants : orange trees, lemon trees.
  • Fruit plants and other tree species : blueberry bushes, currant bushes, yew trees, olive trees.
  • Indoor plants : Yucca palms, Ficus or Benjamini, Dracaena or dragon tree, cacti, rubber trees, orchids, poinsettia.
  • Outside and hedge plants : boxwood, laurel and laurel cherry, ivy, hydrangeas, camellias, oleanders, roses, grapevines or infestation of entire vineyards.