If you discover scale insects on your plant, it is not only annoying, but also requires quick action - scale insects can quickly spread to other plants and cause a lot of destruction. In this article we have summarized how you can combat scale insects effectively and permanently.
How can you combat scale insects effectively?
To effectively combat scale insects, isolate the affected plant, remove damaged shoots and flowers and rinse the plant. Use home remedies such as oil, soapy water or garlic or commercially available chemicals. Alternatively, beneficial insects such as parasitic wasps or ladybirds can be used.
How to recognize a scale insect infestation
It is usually not difficult to recognize a scale insect infestation on your plant. Unfortunately, the pests are not clearly visible right from the start, so damage has often already occurred before the plant shows any signs of infestation. Look for signs of stickiness or a whitish coating on the top of the leaves. This sticky substance is the “honey” of the scale insects. For example, this honey also attracts ants, which is why the appearance of them is another sign of the presence of scale insects. Other clues may include crusted shoots, deformed flowers and leaves, and discoloration or loss of leaves.
Many ways and means of combating 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 infestation of other plants nearby. The following immediate measures can help:
- Isolate the infected plant (if possible) and provide a bright and cool quarantine. Cold can help eliminate scale insects;
- Remove severely damaged or dead shoots and flowers;
- Rinse more robust plants with water.
In addition to the immediate measures to prevent spread, a suitable means of repelling the pests must be selected. There are a variety of products and procedures that come into question. The choice always depends on how severe the infestation is, what kind of plant it is and whether it is indoors or in the garden. In addition, in many cases a home remedy can also be used, meaning that chemicals can often be dispensed with. There are also options for manual, biological and chemical control as well as the use of beneficial insects.
Scale insects can be reduced with a strong shower
Toothbrush and water: mechanical removal
In most cases, the mechanical removal of scale insects does not work as a standalone control approach, but can be used as a first immediate measure, especially in cases of severe infestation. For plants in the garden, take a water hose and a toothbrush or, for plants indoors, a wet washcloth and begin manually rinsing the leaves completely and rinsing 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.
But make sure that you only apply as much pressure as your plant can tolerate without causing further damage - it is better to avoid mechanical removal if it is sensitive plants. Citrus plants and palm trees, for example, benefit greatly from this measure as they are not harmed by toothbrushing. It's 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 systematically combated 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 mechanical removal before treating the entire plant with it - this will prevent the plant from being further damaged by intolerance. The following are particularly suitable home remedies for controlling scale insects:
- Oil;
- Spirit and alcohol;
- Soap and dishwashing liquid;
- other plant remedies;
- Coffee, tea and milk; as well as
- Tobacco or nicotine.
Various oils
On the biological home remedies side, various oils have proven to be useful as pests against scale insects. The oil structure clogs the scale insects' airways, which is why they suffocate within a short time. Since oil is not a contact poison, you can benefit from fairly natural control. 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 scale insects. Since this process is lengthy, it is recommended in combination with other home remedies. The process can also be accelerated if you mix the oil with water and spray it on the entire plant.
Spirits and alcohol
You should proceed carefully when using alcohol, as this could damage many sensitive plants. Spirit is particularly recommended if your plant has thick skin - such as cacti or palm trees. Mix high-percentage alcohol or denatured alcohol with a little water and squeeze the mixture onto each individual scale insect while the infestation is still small. The mixture penetrates the shell of the pests and kills them. However, subsequent repotting is strongly recommended.
Soap and dishwashing liquid
A mixture of detergent, water and vinegar can also help. Spray the affected plant completely with this mixture and leave it to work for a few hours before giving the plant a good shower. Various effective combinations are possible here: pure vinegar or soapy water, for example, or a mixture of water, detergent and spirit works if it is a more robust plant.
Make sure that the soap you use is free of fragrances and other artificial additives so that the plant can be treated as gently as possible. A good approach is therefore to use pure soap and dissolve it in water to make your own dishwashing liquid. Soft soap is even better suited for making soapy water, as its consistency means it dissolves more quickly in water.
Soap suds are an efficient home remedy against scale insects
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 small infestation can be contained by sticking garlic cloves into the soil of a potted plant, which will drive away the garlic-hating pests. Alternatively, you can boil a decoction of chopped garlic and apply it with a spray bottle.
Especially in the garden, it is a good idea to make a manure from nettles. It is not advisable to do this indoors as the manure develops a strong smell. Soak nettles covered in a large container of water for three days, stirring 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 to make 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 onto the plant. A combination of tea and coffee has also proven to be effective - and ensures a pleasant smell in the home. You can also add the coffee grounds directly to the soil in the pot, where they act as a pest control and fertilizer. Alternatively, a mixture of milk and water can be used. To do this, however, the milk should be briefly boiled beforehand and then poured cold over the plant.
Tobacco or nicotine
The last possible home remedy is to use tobacco or nicotine. Pour hot water over tobacco or cigarette ash and let the mixture stand for about an hour before sieving it and brushing or spraying it onto the affected plant. Tobacco or cigarette ash on the plant soil can also increase the desired effect. But here too, caution is advised: this procedure is not for sensitive plants!
Special combat from trade
In addition to fighting scale insects with home remedies, which in some cases means you can get by without chemicals, specialist retailers also offer special pest and plant protection products. The advantage of these products is that they are particularly effective and the fight against them is therefore long-lasting and effective. Be careful not to use biological contact poisons such as pyrethrum, as these cannot penetrate the scale insect's shell 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 released onto the plant as a natural predator.
These remedies are suitable
Suitable means of chemical control are, above all, ready-to-use oil-based sprays such as Neudorff Promanal (€9.00 at Amazon). This product suffocates the pests, gives the leaves a beautiful shine and at the same time does not affect other endangered insects (such as bees). Lizetan-based sprays can also be used well for control purposes. Lizetan is particularly gentle, so 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. Sticks with this active ingredient can also be used for indoor plants.
For experts: Use beneficial insects
Scale insects can also be controlled with beneficial insects
Finally, there is still the possibility of putting scale insects “on the tank” through the targeted use of beneficial insects. However, this approach requires some expert knowledge, as not every type of scale insect is controlled 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 beetles.
Good plant care can prevent scale insects
If your plant is attacked by scale insects, this is in most cases a symptom: scale insects primarily attack plants that are not in good condition. Scale insect infestations are therefore more common, especially in winter or spring, when the plants have to survive with little light. If you have to fight scale insects, it is advisable to prevent a new infestation and to pay particular attention to the care of the plant after they have been eliminated. This primarily includes these measures:
- Make sure your plant gets enough light;
- Pay attention to the room climate when it comes to houseplants and avoid leaving them too warm;
- Avoid nutrient deficiencies and only use small amounts when fertilizing with nitrogen-containing products;
- The soil must be sufficiently loosened;
- Water with enough water and make sure that there is no accumulation of waterlogging.
Especially with fruit trees, it can also be useful to treat the trunk with appropriate bark care and to promote the proliferation of beneficial insects in the garden.
Background
There are many types of scale insects
Not all scale insects are the same: in fact, there are over 4,000 different species of this pest that attacks 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 which species it is. In our latitude it is often the case that one of the following scale insect species is responsible for damaging your plant:
- Cap scale insect: These black, black-brown to brown scale insects are characterized by a flat cap that can be easily removed with a needle. It belongs to the largest group of scale insects and is very widespread.
- Scale scale insects: Scale scale insects are also widespread and are black, black-brown or brown in color, and in some cases also reddish. In contrast to the cap scale insect, however, the cap is highly arched and attached to the skin on the back, so that it cannot be lifted.
- Comma scale insect: These gray to white scale insects have an elongated, slightly domed lid and are found primarily on fruit trees. The name comes from the shape of the pest.
- Cochineal scalefly: Cochineal scalefly have a purple-red body covered in a white to gray wax. Because their bodies contain a high concentration of carminic acid, the pests appear bright red once they are crushed.
- Mealybugs: This is a subspecies of scale insects that can be easily recognized because it produces and leaves a substance on the leaves that looks like small white cotton balls looks.
- 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.
There are very different types of scale insects
Omnivorous scale insect: various plants can be affected
Mealybugs and scale insects are not gourmets, but downright omnivores. They can occur 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 particularly include the following:
- Citrus plants: orange trees, lemon trees.
- Fruit plants and other tree species: blueberry bushes, currant bushes, yews, olive trees.
- Houseplants: Yucca palms, Ficus or Benjamini, Dracaena or dragon tree, cacti, rubber trees, orchids, poinsettias.
- Outdoor and hedge plants: Boxwood, laurel and laurel cherry, ivy, hydrangeas, camellias, oleanders, roses, grapevines or infestation of entire vineyards.
