At first, pests on indoor plants live inconspicuously in secret and one wonders why the plants no longer look fit and vital. If you look closely, you will quickly discover their traces: They leave sticky excretions on leaves or on the planter. Gardener Brigitte Goss explains how to drive away the troublemakers as naturally as possible.
If the plant looks weakened, it is usually worth checking it carefully for pests. They can usually be recognized by their sticky surfaces. Don’t forget the underside of the leaves.
Recognize and fight mealybugs and scale insects
Woolly lice and scale insects are primarily found on woody plants. Both types of louse damage the plants by sucking the sap from different parts of the plant. The plants react with stunted growth and crippling. The lice are often invisible at first glance.
They hide under cover-like protective shields and woolly excretions. The eggs of the pests are also located under a shield or a layer of wax, well protected like in a capsule.
Container plants, such as citrus plants or oleanders, but also orchids, succulents and cacti are often affected. Mealybugs and scale insects are very annoying and can spread quickly. If a plant is infected, it should be quickly separated and treated so that other plants are not infected.
This is how you get rid of woolen insects and scale insects on indoor plants
Mechanically remove lice
If the pests are sitting on woody parts of the plant, you can carefully brush off the affected parts of the plant and, if possible, wash the leaves off. Showering in the shower or bathtub is ideal. Pots and sticks should also be cleaned. Brigitte Goss recommends replacing the earth completely. The pests can also hide in the coarse soil of the orchids – showering alone is not enough here.
Oil preparations against lice
Organic preparations with paraffin or rapeseed oil from specialist retailers have also proven themselves against scale insects and mealybugs. But first test on a leaf beforehand whether the plant tolerates the agent well and does not react with wilted leaves or leaf discoloration. The infected plant can be sprayed with a rapeseed oil preparation up to three times a year at intervals of seven to ten days. (Paraffin oil preparations should only be treated twice a year, at least two weeks apart.) The agent must reach all parts of the plant, i.e. treat leaves, stems and flowers from all sides. Find a shady place for the treatment. Sun exposure on freshly treated leaves can cause burns.
In the event of severe pest infestation, Brigitte Goss recommends finished products from specialist retailers. These are safer than products that you mix yourself and have the advantage that they are tested for plant compatibility. In the case of a slight infestation, rapeseed oil can be mixed with water and detergent and used. Incidentally, this mixture not only helps against lice, but also against spider mites, which just as much like to be around the garden.
Recipe 1: Mixture of rapeseed oil, water and washing-up liquid
- rapeseed oil
- washing-up liquid
Mix 1 part rapeseed oil with 4 parts water and a little washing-up liquid and spray the plant. But be careful: For us this application is harmless, but some plants do not tolerate rapeseed oil well. So try it out on a leaf beforehand and wait a day to see how the plants react. Some plants, especially orchids, could be sensitive to this. The treatment should be repeated after about ten days.
Potash solution and alcohol against lice
Treatment with potassium soap solution and alcohol also help against lice. In the event of severe infestation, the plants are fully sprayed and particularly infested parts of the plant are washed off with the solution or brushed on.
Recipe 2: potassium soap solution and alcohol against lice
- 15-30 g potash soap
- 1 liter of hot water
- 5 ml of alcohol
Dissolve the potash soap in one liter of hot water. Add 5 ml of alcohol. Spray the cooled mixture on the infected parts of the plant.