Hello. In the attached picture the presence of scale insects can be seen (Scale insects in ornamental plants - pest management).
First of all, it is recommended to remove the heavily affected leaves. Then, to control scale insects, it is recommended to apply treatments with insecticides such as and , alternatively. More precisely, the first treatment is recommended to be carried out with , in a dose of 7.5 ml/10 L water, and after 7 days another treatment can be applied with , in a dose of 3 g/10 L water. To increase the effectiveness of the insecticides, it is recommended to add an adjuvant such as , in a dose of 2 ml/10 L to the solutions. Spray the solutions as finely as possible, so as to achieve an even distribution on the plant, both on the underside and topside of the leaves and on the stem (). After they die, these pests can remain on the stem and leaves, so it is recommended to remove them with a damp sponge.
Then, 7-10 days after the end of the treatments, to support the regeneration of the plants after this stressful conditions, you can consider applying a fertilizer such as , as recommended in the product description. From spring onwards, and during the growing season, you can consider the regular application of a fertilizer with a revitalizing effect on plants, such as or , according to the instructions in the product description.